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I have a variable in PHP, and I need its value in my JavaScript code. How can I get my variable from PHP to JavaScript?
I have code that looks like this:
<?php
$val = $myService->getValue(); // Makes an API and database call
On the same page, I have JavaScript code that needs the value of the $val variable to be passed as a parameter:
<script>
myPlugin.start($val); // I tried this, but it didn't work
<?php myPlugin.start($val); ?> // This didn't work either
myPlugin.start(<?=$val?>); // This works sometimes, but sometimes it fails
</script>
There are actually several approaches to do this. Some require more overhead than others, and some are considered better than others.
In no particular order:
Use AJAX to get the data you need from the server.
Echo the data into the page somewhere, and use JavaScript to get the information from the DOM.
Echo the data directly to JavaScript.
In this post, we'll examine each of the above methods, and see the pros and cons of each, as well as how to implement them.
1. Use AJAX to get the data you need from the server
This method is considered the best, because your server side and client side scripts are completely separate.
Pros
Better separation between layers - If tomorrow you stop using PHP, and want to move to a servlet, a REST API, or some other service, you don't have to change much of the JavaScript code.
More readable - JavaScript is JavaScript, PHP is PHP. Without mixing the two, you get more readable code on both languages.
Allows for asynchronous data transfer - Getting the information from PHP might be time/resources expensive. Sometimes you just don't want to wait for the information, load the page, and have the information reach whenever.
Data is not directly found on the markup - This means that your markup is kept clean of any additional data, and only JavaScript sees it.
Cons
Latency - AJAX creates an HTTP request, and HTTP requests are carried over network and have network latencies.
State - Data fetched via a separate HTTP request won't include any information from the HTTP request that fetched the HTML document. You may need this information (e.g., if the HTML document is generated in response to a form submission) and, if you do, will have to transfer it across somehow. If you have ruled out embedding the data in the page (which you have if you are using this technique) then that limits you to cookies/sessions which may be subject to race conditions.
Implementation Example
With AJAX, you need two pages, one is where PHP generates the output, and the second is where JavaScript gets that output:
get-data.php
/* Do some operation here, like talk to the database, the file-session
* The world beyond, limbo, the city of shimmers, and Canada.
*
* AJAX generally uses strings, but you can output JSON, HTML and XML as well.
* It all depends on the Content-type header that you send with your AJAX
* request. */
echo json_encode(42); // In the end, you need to `echo` the result.
// All data should be `json_encode`-d.
// You can `json_encode` any value in PHP, arrays, strings,
// even objects.
index.php (or whatever the actual page is named like)
<!-- snip -->
<script>
fetch("get-data.php")
.then((response) => {
if(!response.ok){ // Before parsing (i.e. decoding) the JSON data,
// check for any errors.
// In case of an error, throw.
throw new Error("Something went wrong!");
}
return response.json(); // Parse the JSON data.
})
.then((data) => {
// This is where you handle what to do with the response.
alert(data); // Will alert: 42
})
.catch((error) => {
// This is where you handle errors.
});
</script>
<!-- snip -->
The above combination of the two files will alert 42 when the file finishes loading.
Some more reading material
Using the Fetch API
How do I return the response from an asynchronous call?
2. Echo the data into the page somewhere, and use JavaScript to get the information from the DOM
This method is less preferable to AJAX, but it still has its advantages. It's still relatively separated between PHP and JavaScript in a sense that there is no PHP directly in the JavaScript.
Pros
Fast - DOM operations are often quick, and you can store and access a lot of data relatively quickly.
Cons
Potentially Unsemantic Markup - Usually, what happens is that you use some sort of <input type=hidden> to store the information, because it's easier to get the information out of inputNode.value, but doing so means that you have a meaningless element in your HTML. HTML has the <meta> element for data about the document, and HTML 5 introduces data-* attributes for data specifically for reading with JavaScript that can be associated with particular elements.
Dirties up the Source - Data that PHP generates is outputted directly to the HTML source, meaning that you get a bigger and less focused HTML source.
Harder to get structured data - Structured data will have to be valid HTML, otherwise you'll have to escape and convert strings yourself.
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
With this, the idea is to create some sort of element which will not be displayed to the user, but is visible to JavaScript.
index.php
<!-- snip -->
<div id="dom-target" style="display: none;">
<?php
$output = "42"; // Again, do some operation, get the output.
echo htmlspecialchars($output); /* You have to escape because the result
will not be valid HTML otherwise. */
?>
</div>
<script>
var div = document.getElementById("dom-target");
var myData = div.textContent;
</script>
<!-- snip -->
3. Echo the data directly to JavaScript
This is probably the easiest to understand.
Pros
Very easily implemented - It takes very little to implement this, and understand.
Does not dirty source - Variables are outputted directly to JavaScript, so the DOM is not affected.
Cons
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
Implementation is relatively straightforward:
<!-- snip -->
<script>
var data = <?php echo json_encode("42", JSON_HEX_TAG); ?>; // Don't forget the extra semicolon!
</script>
<!-- snip -->
Good luck!
I usually use data-* attributes in HTML.
<div
class="service-container"
data-service="<?= htmlspecialchars($myService->getValue()) ?>"
>
</div>
<script>
$(document).ready(function() {
$('.service-container').each(function() {
var container = $(this);
var service = container.data('service');
// Var "service" now contains the value of $myService->getValue();
});
});
</script>
This example uses jQuery, but it can be adapted for another library or vanilla JavaScript.
You can read more about the dataset property here: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.dataset
I'm going to try a simpler answer:
Explanation of the problem
First, let's understand the flow of events when a page is served from our server:
First PHP is run, it generates the HTML that is served to the client.
Then, PHP "dies" (i.e. it literally stops running) as that HTML is delivered to the client. I'd like to emphasize that once the code leaves the server, PHP has stopped being part of the page load, and the server has no access access to it anymore.
Then, when the HTML with JavaScript reaches the client, that can then execute the JavaScript on that HTML, provided it is valid Javascript.
So really, the core thing to remember here is that HTTP is stateless. Once a request left the server, the server can not touch it. So, that leaves our options to:
Send more requests from the client after the initial request is done.
Encode what the server had to say in the initial request.
Solutions
That's the core question you should be asking yourself is:
Am I writing a website or an application?
Websites are mainly page based, and the page load times needs to be as fast as possible (for example - Wikipedia). Web applications are more AJAX heavy and perform a lot of round trips to get the client fast information (for example - a stock dashboard).
Website
Sending more requests from the client after the initial request is done is slow as it requires more HTTP requests which have significant overhead. Moreover, it requires asynchronousity as making an AJAX request requires a handler for when it's complete.
I would not recommend making another request unless your site is an application for getting that information from the server.
You want fast response times which have a huge impact on conversion and load times. Making Ajax requests is slow for the initial uptime in this case and unneeded.
You have two ways to tackle the issue
Set a cookie - cookies are headers sent in HTTP requests that both the server and client can read.
Encode the variable as JSON - JSON looks very close to JavaScript objects and most JSON objects are valid JavaScript variables.
Setting a cookie is really not very difficult, you just assign it a value:
setcookie("MyCookie", $value); // Sets the cookie to the value, remember, do not
// Set it with HTTP only to true.
Then, you can read it with JavaScript using document.cookie:
Here is a short hand rolled parser, but the answer I linked to right above this has better tested ones:
var cookies = document.cookie.split(";").
map(function(el){ return el.split("="); }).
reduce(function(prev,cur){ prev[cur[0]] = cur[1]; return prev },{});
alert(cookies["MyCookie"]); // Value set with PHP.
Cookies are good for a little data. This is what tracking services often do.
Once we have more data, we can encode it with JSON inside a JavaScript variable instead:
<script>
var myServerData = <?=json_encode($value)?>; // Don't forget to sanitize
//server data
</script>
Assuming $value is json_encodeable on the PHP side (it usually is). This technique is what Stack Overflow does with its chat for example (only using .NET instead of PHP).
Application
If you're writing an application - suddenly the initial load time isn't always as important as the ongoing performance of the application, and it starts to pay off to load data and code separately.
My answer here explains how to load data using AJAX in JavaScript:
function callback(data){
// What do I do with the response?
}
var httpRequest = new XMLHttpRequest;
httpRequest.onreadystatechange = function(){
if (httpRequest.readyState === 4) { // Request is done
if (httpRequest.status === 200) { // successfully
callback(httpRequest.responseText); // We're calling our method
}
}
};
httpRequest.open('GET', "/echo/json");
httpRequest.send();
Or with jQuery:
$.get("/your/url").done(function(data){
// What do I do with the data?
});
Now, the server just needs to contain a /your/url route/file that contains code that grabs the data and does something with it, in your case:
<?php
$val = myService->getValue(); // Makes an API and database call
header("Content-Type: application/json"); // Advise client of response type
echo json_encode($val); // Write it to the output
This way, our JavaScript file asks for the data and shows it rather than asking for code or for layout. This is cleaner and starts to pay off as the application gets higher. It's also better separation of concerns and it allows testing the client side code without any server side technology involved which is another plus.
Postscript: You have to be very aware of XSS attack vectors when you inject anything from PHP to JavaScript. It's very hard to escape values properly and it's context sensitive. If you're unsure how to deal with XSS, or unaware of it - please read this OWASP article, this one and this question.
<script>
var jsvar = <?php echo json_encode($PHPVar); ?>;
</script>
json_encode() requires:
PHP 5.2.0 or more
$PHPVar encoded as UTF-8, Unicode.
Simply use one of the following methods.
<script type="text/javascript">
var js_variable = '<?php echo $php_variable;?>';
<script>
OR
<script type="text/javascript">
var js_variable = <?php echo json_encode($php_variable); ?>;
</script>
I quite like the way the WordPress works with its enqueue and localize functions, so following that model, I wrote a simple class for putting a scripts into page according to the script dependencies, and for making additional data available for the script.
class mHeader {
private $scripts = array();
/**
* #param string $id Unique script identifier
* #param string $src Script src attribute
* #param array $deps An array of dependencies ( script identifiers ).
* #param array $data An array, data that will be json_encoded and available to the script.
*/
function enqueue_script($id, $src, $deps = array(), $data = array()) {
$this->scripts[$id] = array('src' => $src, 'deps' => $deps, 'data' => $data);
}
private function dependencies($script) {
if ($script['deps']) {
return array_map(array($this, 'dependencies'), array_intersect_key($this->scripts, array_flip($script['deps'])));
}
}
private function _unset($key, &$deps, &$out) {
$out[$key] = $this->scripts[$key];
unset($deps[$key]);
}
private function flattern(&$deps, &$out = array()) {
foreach($deps as $key => $value) {
empty($value) ? $this->_unset($key, $deps, $out) : $this->flattern( $deps[$key], $out);
}
}
function print_scripts() {
if (!$this->scripts)
return;
$deps = array_map(array($this, 'dependencies'), $this->scripts);
while ($deps)
$this->flattern($deps, $js);
foreach($js as $key => $script) {
$script['data'] && printf("<script> var %s = %s; </script>" . PHP_EOL, key($script['data']), json_encode(current( $script['data'])));
echo "<script id=\"$key-js\" src=\"$script[src]\" type=\"text/javascript\"></script>" . PHP_EOL;
}
}
}
The call to the enqueue_script() function is for adding script, setting the source and dependencies on other scripts, and additional data needed for the script.
$header = new mHeader();
$header->enqueue_script('jquery-ui', '//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js', array('jquery'));
$header->enqueue_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js');
$header->enqueue_script('custom-script', '//custom-script.min.js', array('jquery-ui'), array('mydata' => array('value' => 20)));
$header->print_scripts();
And, print_scripts() method of the above example will send this output:
<script id="jquery-js" src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script id="jquery-ui-js" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js" type="text/javascript"></script>
<script> var mydata = {"value":20}; </script>
<script id="custom-script-js" src="//custom-script.min.js" type="text/javascript"></script>
Regardless the fact that the script 'jquery' is enqueued after the 'jquery-ui', it is printed before because it is defined in 'jquery-ui' that it depends on 'jquery'.
Additional data for the 'custom-script' are inside a new script block and are placed in front of it, it contains mydata object that holds additional data, now available to 'custom-script'.
Try this:
<?php
echo "<script> var x = " . json_encode($phpVariable) . "</script>";
?>
--
-After trying this for a while
Although it works, however it slows down the performance. As PHP is a server-side script while JavaScript is a user side.
I have come out with an easy method to assign JavaScript variables using PHP.
It uses HTML5 data attributes to store PHP variables and then it's assigned to JavaScript on page load.
Example:
<?php
$variable_1 = "QNimate";
$variable_2 = "QScutter";
?>
<span id="storage" data-variable-one="<?php echo $variable_1; ?>" data-variable-two="<?php echo $variable_2; ?>"></span>
<?php
Here is the JavaScript code
var variable_1 = undefined;
var variable_2 = undefined;
window.onload = function(){
variable_1 = document.getElementById("storage").getAttribute("data-variable-one");
variable_2 = document.getElementById("storage").getAttribute("data-variable-two");
}
Convert the data into JSON
Call AJAX to recieve JSON file
Convert JSON into Javascript object
Example:
STEP 1
<?php
$servername = "localhost";
$username = "";
$password = "";
$dbname = "";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, name, image FROM phone";
$result = $conn->query($sql);
while($row = $result->fetch_assoc()){
$v[] = $row;
}
echo json_encode($v);
$conn->close();
?>
STEP 2
function showUser(fnc) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// STEP 3
var p = JSON.parse(this.responseText);
}
}
}
myPlugin.start($val); // Tried this, didn't work
It doesn't work because $val is undefined as far as JavaScript is concerned, i.e. the PHP code did not output anything for $val. Try viewing the source in your browser and here is what you'll see:
myPlugin.start(); // I tried this, and it didn't work
And
<?php myPlugin.start($val); ?> // This didn't work either
This doesn't work because PHP will try to treat myPlugin as a constant and when that fails it will try to treat it as the string 'myPlugin' which it will try to concatenate with the output of the PHP function start() and since that is undefined it will produce a fatal error.
And
myPlugin.start(<?=$val?> // This works sometimes, but sometimes it fails
While this is most likely to work, since the PHP code is producing valid JavaScript with the expected arguments, if it fails, chances are it's because myPlugin isn't ready yet. Check your order of execution.
Also you should note that the PHP code output is insecure and should be filtered with json_encode().
EDIT
Because I didn't notice the missing parenthesis in myPlugin.start(<?=$val?> :-\
As #Second Rikudo points out, for it to work correctly $val would need to contain the closing parenthesis, for example: $val="42);"
Meaning that the PHP will now produce myPlugin.start(42); and will work as expected when executed by the JavaScript code.
Here is is the trick:
Here is your 'PHP' to use that variable:
<?php
$name = 'PHP variable';
echo '<script>';
echo 'var name = ' . json_encode($name) . ';';
echo '</script>';
?>
Now you have a JavaScript variable called 'name', and here is your JavaScript code to use that variable:
<script>
console.log("I am everywhere " + name);
</script>
Let's say your variable is always integer. In that case this is easier:
<?PHP
$number = 4;
echo '<script>';
echo 'var number = ' . $number . ';';
echo 'alert(number);';
echo '</script>';
?>
Output:
<script>var number = 4;alert(number);</script>
Let's say your variable is not an integer, but if you try above method you will get something like this:
<script>var number = abcd;alert(number);</script>
But in JavaScript this is a syntax error.
So in PHP we have a function call json_encode that encode string to a JSON object.
<?PHP
$number = 'abcd';
echo '<script>';
echo 'var number = ' . json_encode($number) . ';';
echo 'alert(number);';
echo '</script>';
?>
Since abcd in JSON is "abcd", it looks like this:
<script>var number = "abcd";alert(number);</script>
You can use same method for arrays:
<?PHP
$details = [
'name' => 'supun',
'age' => 456,
'weight' => '55'
];
echo '<script>';
echo 'var details = ' . json_encode($details) . ';';
echo 'alert(details);';
echo 'console.log(details);';
echo '</script>';
?>
And your JavaScript code looks like this:
<script>var details = {"name":"supun","age":456,"weight":"55"};alert(details);console.log(details);</script>
Console output
I'll assume that the data to transmit is a string.
As other commenters have stated, AJAX is one possible solution, but the cons outweigh the pros: it has a latency and it is harder to program (it needs the code to retrieve the value both server- and client-side), when a simpler escaping function should suffice.
So, we're back to escaping. json_encode($string) works if you encode the source string as UTF-8 first in case it is not already, because json_encode requires UTF-8 data. If the string is in ISO-8859-1 then you can simply use json_encode(utf8_encode($string)); otherwise you can always use iconv to do the conversion first.
But there's a big gotcha. If you're using it in events, you need to run htmlspecialchars() on the result in order to make it correct code. And then you have to either be careful to use double quotes to enclose the event, or always add ENT_QUOTES to htmlspecialchars. For example:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Fails:
//echo '<body onload="alert(', json_encode($myvar), ');">';
// Fails:
//echo "<body onload='alert(", json_encode($myvar), ");'>";
// Fails:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar)), ");'>";
// Works:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar), ENT_QUOTES), ");'>";
// Works:
echo '<body onload="alert(', htmlspecialchars(json_encode($myvar)), ');">';
echo "</body>";
However, you can't use htmlspecialchars on regular JavaScript code (code enclosed in <script>...</script> tags). That makes use of this function prone to mistakes, by forgetting to htmlspecialchars the result when writing event code.
It's possible to write a function that does not have that problem, and can be used both in events and in regular JavaScript code, as long as you enclose your events always in single quotes, or always in double quotes. Here is my proposal, requiring them to be in double quotes (which I prefer):
<?php
// Optionally pass the encoding of the source string, if not UTF-8
function escapeJSString($string, $encoding = 'UTF-8')
{
if ($encoding != 'UTF-8')
$string = iconv($encoding, 'UTF-8', $string);
$flags = JSON_HEX_TAG|JSON_HEX_AMP|JSON_HEX_APOS|JSON_HEX_QUOT|JSON_UNESCAPED_SLASHES;
$string = substr(json_encode($string, $flags), 1, -1);
return "'$string'";
}
The function requires PHP 5.4+. Example usage:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Note use of double quotes to enclose the event definition!
echo '<body onload="alert(', escapeJSString($myvar), ');">';
// Example with regular code:
echo '<script>alert(', escapeJSString($myvar), ');</script>';
echo '</body>';
After much research, I found the easiest method is to pass all kinds of variables easily.
In the server script, you have two variables, and you are trying to send them to the client scripts:
$php_var1 ="Hello world";
$php_var2 ="Helloow";
echo '<script>';
echo 'var js_variable1= ' . json_encode($php_var1) . ';';
echo 'var js_variable2= ' . json_encode($php_var2) . ';';
echo '</script>';
In any of your JavaScript code called on the page, simply call those variables.
PHP
$fruits = array("apple" => "yellow", "strawberry" => "red", "kiwi" => "green");
<script>
var color = <?php echo json_encode($fruits) ?>;
</script>
<script src="../yourexternal.js"></script>
JS (yourexternal.js)
alert("The apple color is" + color['apple'] + ", the strawberry color is " + color['strawberry'] + " and the kiwi color is " + color['kiwi'] + ".");
OUTPUT
The apple color is yellow, the strawberry color is red and the kiwi
color is green.
This is what works for me in 2022, I used this solution to get the email of the current user
I create a shortcode using PHP and added it to PHP .function:
function my_get_current_user_email(){
$current_user = wp_get_current_user();
$email = $current_user->user_email;
return $email;
}
add_shortcode( 'get_email', 'my_get_current_user_email');
Then use a div to wrap the shortcode:
<div id="target-content" style="display: none;">
[get_email]
</div>
Finally, access the content of the Div with JavaScript:
const databox = document.getElementById("target-content");
const dataContent = databox.textContent;
console.log(dataContent)
This work perfectly for what I wanted and I hope it will work for you too.
As per your code
<$php
$val = $myService->getValue(); // Makes an API and database call
echo '<span id="value">'.$val.'</span>';
$>
Now you can get value using DOM, use innerHTML of span id, in this case you don't need to do any call to server, or Ajax or another thing.
Your page will print it using PHP, and you JavaScript will get value using DOM.
<?php
$val = $myService->getValue(); // Makes an API and database call
echo "
<script>
myPlugin.start({$val});
</script> ";
?>
we can do it using php heredoc:
<?php
$inPhpVar = "i am php var";
$ScriptInline = <<<JS
<script>
alert('{$inPhpVar} that used in js code');
</script>
JS;
echo $ScriptInline;
?>
Want to improve this post? Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted.
I have a variable in PHP, and I need its value in my JavaScript code. How can I get my variable from PHP to JavaScript?
I have code that looks like this:
<?php
$val = $myService->getValue(); // Makes an API and database call
On the same page, I have JavaScript code that needs the value of the $val variable to be passed as a parameter:
<script>
myPlugin.start($val); // I tried this, but it didn't work
<?php myPlugin.start($val); ?> // This didn't work either
myPlugin.start(<?=$val?>); // This works sometimes, but sometimes it fails
</script>
There are actually several approaches to do this. Some require more overhead than others, and some are considered better than others.
In no particular order:
Use AJAX to get the data you need from the server.
Echo the data into the page somewhere, and use JavaScript to get the information from the DOM.
Echo the data directly to JavaScript.
In this post, we'll examine each of the above methods, and see the pros and cons of each, as well as how to implement them.
1. Use AJAX to get the data you need from the server
This method is considered the best, because your server side and client side scripts are completely separate.
Pros
Better separation between layers - If tomorrow you stop using PHP, and want to move to a servlet, a REST API, or some other service, you don't have to change much of the JavaScript code.
More readable - JavaScript is JavaScript, PHP is PHP. Without mixing the two, you get more readable code on both languages.
Allows for asynchronous data transfer - Getting the information from PHP might be time/resources expensive. Sometimes you just don't want to wait for the information, load the page, and have the information reach whenever.
Data is not directly found on the markup - This means that your markup is kept clean of any additional data, and only JavaScript sees it.
Cons
Latency - AJAX creates an HTTP request, and HTTP requests are carried over network and have network latencies.
State - Data fetched via a separate HTTP request won't include any information from the HTTP request that fetched the HTML document. You may need this information (e.g., if the HTML document is generated in response to a form submission) and, if you do, will have to transfer it across somehow. If you have ruled out embedding the data in the page (which you have if you are using this technique) then that limits you to cookies/sessions which may be subject to race conditions.
Implementation Example
With AJAX, you need two pages, one is where PHP generates the output, and the second is where JavaScript gets that output:
get-data.php
/* Do some operation here, like talk to the database, the file-session
* The world beyond, limbo, the city of shimmers, and Canada.
*
* AJAX generally uses strings, but you can output JSON, HTML and XML as well.
* It all depends on the Content-type header that you send with your AJAX
* request. */
echo json_encode(42); // In the end, you need to `echo` the result.
// All data should be `json_encode`-d.
// You can `json_encode` any value in PHP, arrays, strings,
// even objects.
index.php (or whatever the actual page is named like)
<!-- snip -->
<script>
fetch("get-data.php")
.then((response) => {
if(!response.ok){ // Before parsing (i.e. decoding) the JSON data,
// check for any errors.
// In case of an error, throw.
throw new Error("Something went wrong!");
}
return response.json(); // Parse the JSON data.
})
.then((data) => {
// This is where you handle what to do with the response.
alert(data); // Will alert: 42
})
.catch((error) => {
// This is where you handle errors.
});
</script>
<!-- snip -->
The above combination of the two files will alert 42 when the file finishes loading.
Some more reading material
Using the Fetch API
How do I return the response from an asynchronous call?
2. Echo the data into the page somewhere, and use JavaScript to get the information from the DOM
This method is less preferable to AJAX, but it still has its advantages. It's still relatively separated between PHP and JavaScript in a sense that there is no PHP directly in the JavaScript.
Pros
Fast - DOM operations are often quick, and you can store and access a lot of data relatively quickly.
Cons
Potentially Unsemantic Markup - Usually, what happens is that you use some sort of <input type=hidden> to store the information, because it's easier to get the information out of inputNode.value, but doing so means that you have a meaningless element in your HTML. HTML has the <meta> element for data about the document, and HTML 5 introduces data-* attributes for data specifically for reading with JavaScript that can be associated with particular elements.
Dirties up the Source - Data that PHP generates is outputted directly to the HTML source, meaning that you get a bigger and less focused HTML source.
Harder to get structured data - Structured data will have to be valid HTML, otherwise you'll have to escape and convert strings yourself.
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
With this, the idea is to create some sort of element which will not be displayed to the user, but is visible to JavaScript.
index.php
<!-- snip -->
<div id="dom-target" style="display: none;">
<?php
$output = "42"; // Again, do some operation, get the output.
echo htmlspecialchars($output); /* You have to escape because the result
will not be valid HTML otherwise. */
?>
</div>
<script>
var div = document.getElementById("dom-target");
var myData = div.textContent;
</script>
<!-- snip -->
3. Echo the data directly to JavaScript
This is probably the easiest to understand.
Pros
Very easily implemented - It takes very little to implement this, and understand.
Does not dirty source - Variables are outputted directly to JavaScript, so the DOM is not affected.
Cons
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
Implementation is relatively straightforward:
<!-- snip -->
<script>
var data = <?php echo json_encode("42", JSON_HEX_TAG); ?>; // Don't forget the extra semicolon!
</script>
<!-- snip -->
Good luck!
I usually use data-* attributes in HTML.
<div
class="service-container"
data-service="<?= htmlspecialchars($myService->getValue()) ?>"
>
</div>
<script>
$(document).ready(function() {
$('.service-container').each(function() {
var container = $(this);
var service = container.data('service');
// Var "service" now contains the value of $myService->getValue();
});
});
</script>
This example uses jQuery, but it can be adapted for another library or vanilla JavaScript.
You can read more about the dataset property here: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.dataset
I'm going to try a simpler answer:
Explanation of the problem
First, let's understand the flow of events when a page is served from our server:
First PHP is run, it generates the HTML that is served to the client.
Then, PHP "dies" (i.e. it literally stops running) as that HTML is delivered to the client. I'd like to emphasize that once the code leaves the server, PHP has stopped being part of the page load, and the server has no access access to it anymore.
Then, when the HTML with JavaScript reaches the client, that can then execute the JavaScript on that HTML, provided it is valid Javascript.
So really, the core thing to remember here is that HTTP is stateless. Once a request left the server, the server can not touch it. So, that leaves our options to:
Send more requests from the client after the initial request is done.
Encode what the server had to say in the initial request.
Solutions
That's the core question you should be asking yourself is:
Am I writing a website or an application?
Websites are mainly page based, and the page load times needs to be as fast as possible (for example - Wikipedia). Web applications are more AJAX heavy and perform a lot of round trips to get the client fast information (for example - a stock dashboard).
Website
Sending more requests from the client after the initial request is done is slow as it requires more HTTP requests which have significant overhead. Moreover, it requires asynchronousity as making an AJAX request requires a handler for when it's complete.
I would not recommend making another request unless your site is an application for getting that information from the server.
You want fast response times which have a huge impact on conversion and load times. Making Ajax requests is slow for the initial uptime in this case and unneeded.
You have two ways to tackle the issue
Set a cookie - cookies are headers sent in HTTP requests that both the server and client can read.
Encode the variable as JSON - JSON looks very close to JavaScript objects and most JSON objects are valid JavaScript variables.
Setting a cookie is really not very difficult, you just assign it a value:
setcookie("MyCookie", $value); // Sets the cookie to the value, remember, do not
// Set it with HTTP only to true.
Then, you can read it with JavaScript using document.cookie:
Here is a short hand rolled parser, but the answer I linked to right above this has better tested ones:
var cookies = document.cookie.split(";").
map(function(el){ return el.split("="); }).
reduce(function(prev,cur){ prev[cur[0]] = cur[1]; return prev },{});
alert(cookies["MyCookie"]); // Value set with PHP.
Cookies are good for a little data. This is what tracking services often do.
Once we have more data, we can encode it with JSON inside a JavaScript variable instead:
<script>
var myServerData = <?=json_encode($value)?>; // Don't forget to sanitize
//server data
</script>
Assuming $value is json_encodeable on the PHP side (it usually is). This technique is what Stack Overflow does with its chat for example (only using .NET instead of PHP).
Application
If you're writing an application - suddenly the initial load time isn't always as important as the ongoing performance of the application, and it starts to pay off to load data and code separately.
My answer here explains how to load data using AJAX in JavaScript:
function callback(data){
// What do I do with the response?
}
var httpRequest = new XMLHttpRequest;
httpRequest.onreadystatechange = function(){
if (httpRequest.readyState === 4) { // Request is done
if (httpRequest.status === 200) { // successfully
callback(httpRequest.responseText); // We're calling our method
}
}
};
httpRequest.open('GET', "/echo/json");
httpRequest.send();
Or with jQuery:
$.get("/your/url").done(function(data){
// What do I do with the data?
});
Now, the server just needs to contain a /your/url route/file that contains code that grabs the data and does something with it, in your case:
<?php
$val = myService->getValue(); // Makes an API and database call
header("Content-Type: application/json"); // Advise client of response type
echo json_encode($val); // Write it to the output
This way, our JavaScript file asks for the data and shows it rather than asking for code or for layout. This is cleaner and starts to pay off as the application gets higher. It's also better separation of concerns and it allows testing the client side code without any server side technology involved which is another plus.
Postscript: You have to be very aware of XSS attack vectors when you inject anything from PHP to JavaScript. It's very hard to escape values properly and it's context sensitive. If you're unsure how to deal with XSS, or unaware of it - please read this OWASP article, this one and this question.
<script>
var jsvar = <?php echo json_encode($PHPVar); ?>;
</script>
json_encode() requires:
PHP 5.2.0 or more
$PHPVar encoded as UTF-8, Unicode.
Simply use one of the following methods.
<script type="text/javascript">
var js_variable = '<?php echo $php_variable;?>';
<script>
OR
<script type="text/javascript">
var js_variable = <?php echo json_encode($php_variable); ?>;
</script>
I quite like the way the WordPress works with its enqueue and localize functions, so following that model, I wrote a simple class for putting a scripts into page according to the script dependencies, and for making additional data available for the script.
class mHeader {
private $scripts = array();
/**
* #param string $id Unique script identifier
* #param string $src Script src attribute
* #param array $deps An array of dependencies ( script identifiers ).
* #param array $data An array, data that will be json_encoded and available to the script.
*/
function enqueue_script($id, $src, $deps = array(), $data = array()) {
$this->scripts[$id] = array('src' => $src, 'deps' => $deps, 'data' => $data);
}
private function dependencies($script) {
if ($script['deps']) {
return array_map(array($this, 'dependencies'), array_intersect_key($this->scripts, array_flip($script['deps'])));
}
}
private function _unset($key, &$deps, &$out) {
$out[$key] = $this->scripts[$key];
unset($deps[$key]);
}
private function flattern(&$deps, &$out = array()) {
foreach($deps as $key => $value) {
empty($value) ? $this->_unset($key, $deps, $out) : $this->flattern( $deps[$key], $out);
}
}
function print_scripts() {
if (!$this->scripts)
return;
$deps = array_map(array($this, 'dependencies'), $this->scripts);
while ($deps)
$this->flattern($deps, $js);
foreach($js as $key => $script) {
$script['data'] && printf("<script> var %s = %s; </script>" . PHP_EOL, key($script['data']), json_encode(current( $script['data'])));
echo "<script id=\"$key-js\" src=\"$script[src]\" type=\"text/javascript\"></script>" . PHP_EOL;
}
}
}
The call to the enqueue_script() function is for adding script, setting the source and dependencies on other scripts, and additional data needed for the script.
$header = new mHeader();
$header->enqueue_script('jquery-ui', '//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js', array('jquery'));
$header->enqueue_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js');
$header->enqueue_script('custom-script', '//custom-script.min.js', array('jquery-ui'), array('mydata' => array('value' => 20)));
$header->print_scripts();
And, print_scripts() method of the above example will send this output:
<script id="jquery-js" src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script id="jquery-ui-js" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js" type="text/javascript"></script>
<script> var mydata = {"value":20}; </script>
<script id="custom-script-js" src="//custom-script.min.js" type="text/javascript"></script>
Regardless the fact that the script 'jquery' is enqueued after the 'jquery-ui', it is printed before because it is defined in 'jquery-ui' that it depends on 'jquery'.
Additional data for the 'custom-script' are inside a new script block and are placed in front of it, it contains mydata object that holds additional data, now available to 'custom-script'.
Try this:
<?php
echo "<script> var x = " . json_encode($phpVariable) . "</script>";
?>
--
-After trying this for a while
Although it works, however it slows down the performance. As PHP is a server-side script while JavaScript is a user side.
I have come out with an easy method to assign JavaScript variables using PHP.
It uses HTML5 data attributes to store PHP variables and then it's assigned to JavaScript on page load.
Example:
<?php
$variable_1 = "QNimate";
$variable_2 = "QScutter";
?>
<span id="storage" data-variable-one="<?php echo $variable_1; ?>" data-variable-two="<?php echo $variable_2; ?>"></span>
<?php
Here is the JavaScript code
var variable_1 = undefined;
var variable_2 = undefined;
window.onload = function(){
variable_1 = document.getElementById("storage").getAttribute("data-variable-one");
variable_2 = document.getElementById("storage").getAttribute("data-variable-two");
}
Convert the data into JSON
Call AJAX to recieve JSON file
Convert JSON into Javascript object
Example:
STEP 1
<?php
$servername = "localhost";
$username = "";
$password = "";
$dbname = "";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, name, image FROM phone";
$result = $conn->query($sql);
while($row = $result->fetch_assoc()){
$v[] = $row;
}
echo json_encode($v);
$conn->close();
?>
STEP 2
function showUser(fnc) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// STEP 3
var p = JSON.parse(this.responseText);
}
}
}
myPlugin.start($val); // Tried this, didn't work
It doesn't work because $val is undefined as far as JavaScript is concerned, i.e. the PHP code did not output anything for $val. Try viewing the source in your browser and here is what you'll see:
myPlugin.start(); // I tried this, and it didn't work
And
<?php myPlugin.start($val); ?> // This didn't work either
This doesn't work because PHP will try to treat myPlugin as a constant and when that fails it will try to treat it as the string 'myPlugin' which it will try to concatenate with the output of the PHP function start() and since that is undefined it will produce a fatal error.
And
myPlugin.start(<?=$val?> // This works sometimes, but sometimes it fails
While this is most likely to work, since the PHP code is producing valid JavaScript with the expected arguments, if it fails, chances are it's because myPlugin isn't ready yet. Check your order of execution.
Also you should note that the PHP code output is insecure and should be filtered with json_encode().
EDIT
Because I didn't notice the missing parenthesis in myPlugin.start(<?=$val?> :-\
As #Second Rikudo points out, for it to work correctly $val would need to contain the closing parenthesis, for example: $val="42);"
Meaning that the PHP will now produce myPlugin.start(42); and will work as expected when executed by the JavaScript code.
Here is is the trick:
Here is your 'PHP' to use that variable:
<?php
$name = 'PHP variable';
echo '<script>';
echo 'var name = ' . json_encode($name) . ';';
echo '</script>';
?>
Now you have a JavaScript variable called 'name', and here is your JavaScript code to use that variable:
<script>
console.log("I am everywhere " + name);
</script>
Let's say your variable is always integer. In that case this is easier:
<?PHP
$number = 4;
echo '<script>';
echo 'var number = ' . $number . ';';
echo 'alert(number);';
echo '</script>';
?>
Output:
<script>var number = 4;alert(number);</script>
Let's say your variable is not an integer, but if you try above method you will get something like this:
<script>var number = abcd;alert(number);</script>
But in JavaScript this is a syntax error.
So in PHP we have a function call json_encode that encode string to a JSON object.
<?PHP
$number = 'abcd';
echo '<script>';
echo 'var number = ' . json_encode($number) . ';';
echo 'alert(number);';
echo '</script>';
?>
Since abcd in JSON is "abcd", it looks like this:
<script>var number = "abcd";alert(number);</script>
You can use same method for arrays:
<?PHP
$details = [
'name' => 'supun',
'age' => 456,
'weight' => '55'
];
echo '<script>';
echo 'var details = ' . json_encode($details) . ';';
echo 'alert(details);';
echo 'console.log(details);';
echo '</script>';
?>
And your JavaScript code looks like this:
<script>var details = {"name":"supun","age":456,"weight":"55"};alert(details);console.log(details);</script>
Console output
I'll assume that the data to transmit is a string.
As other commenters have stated, AJAX is one possible solution, but the cons outweigh the pros: it has a latency and it is harder to program (it needs the code to retrieve the value both server- and client-side), when a simpler escaping function should suffice.
So, we're back to escaping. json_encode($string) works if you encode the source string as UTF-8 first in case it is not already, because json_encode requires UTF-8 data. If the string is in ISO-8859-1 then you can simply use json_encode(utf8_encode($string)); otherwise you can always use iconv to do the conversion first.
But there's a big gotcha. If you're using it in events, you need to run htmlspecialchars() on the result in order to make it correct code. And then you have to either be careful to use double quotes to enclose the event, or always add ENT_QUOTES to htmlspecialchars. For example:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Fails:
//echo '<body onload="alert(', json_encode($myvar), ');">';
// Fails:
//echo "<body onload='alert(", json_encode($myvar), ");'>";
// Fails:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar)), ");'>";
// Works:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar), ENT_QUOTES), ");'>";
// Works:
echo '<body onload="alert(', htmlspecialchars(json_encode($myvar)), ');">';
echo "</body>";
However, you can't use htmlspecialchars on regular JavaScript code (code enclosed in <script>...</script> tags). That makes use of this function prone to mistakes, by forgetting to htmlspecialchars the result when writing event code.
It's possible to write a function that does not have that problem, and can be used both in events and in regular JavaScript code, as long as you enclose your events always in single quotes, or always in double quotes. Here is my proposal, requiring them to be in double quotes (which I prefer):
<?php
// Optionally pass the encoding of the source string, if not UTF-8
function escapeJSString($string, $encoding = 'UTF-8')
{
if ($encoding != 'UTF-8')
$string = iconv($encoding, 'UTF-8', $string);
$flags = JSON_HEX_TAG|JSON_HEX_AMP|JSON_HEX_APOS|JSON_HEX_QUOT|JSON_UNESCAPED_SLASHES;
$string = substr(json_encode($string, $flags), 1, -1);
return "'$string'";
}
The function requires PHP 5.4+. Example usage:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Note use of double quotes to enclose the event definition!
echo '<body onload="alert(', escapeJSString($myvar), ');">';
// Example with regular code:
echo '<script>alert(', escapeJSString($myvar), ');</script>';
echo '</body>';
After much research, I found the easiest method is to pass all kinds of variables easily.
In the server script, you have two variables, and you are trying to send them to the client scripts:
$php_var1 ="Hello world";
$php_var2 ="Helloow";
echo '<script>';
echo 'var js_variable1= ' . json_encode($php_var1) . ';';
echo 'var js_variable2= ' . json_encode($php_var2) . ';';
echo '</script>';
In any of your JavaScript code called on the page, simply call those variables.
PHP
$fruits = array("apple" => "yellow", "strawberry" => "red", "kiwi" => "green");
<script>
var color = <?php echo json_encode($fruits) ?>;
</script>
<script src="../yourexternal.js"></script>
JS (yourexternal.js)
alert("The apple color is" + color['apple'] + ", the strawberry color is " + color['strawberry'] + " and the kiwi color is " + color['kiwi'] + ".");
OUTPUT
The apple color is yellow, the strawberry color is red and the kiwi
color is green.
This is what works for me in 2022, I used this solution to get the email of the current user
I create a shortcode using PHP and added it to PHP .function:
function my_get_current_user_email(){
$current_user = wp_get_current_user();
$email = $current_user->user_email;
return $email;
}
add_shortcode( 'get_email', 'my_get_current_user_email');
Then use a div to wrap the shortcode:
<div id="target-content" style="display: none;">
[get_email]
</div>
Finally, access the content of the Div with JavaScript:
const databox = document.getElementById("target-content");
const dataContent = databox.textContent;
console.log(dataContent)
This work perfectly for what I wanted and I hope it will work for you too.
As per your code
<$php
$val = $myService->getValue(); // Makes an API and database call
echo '<span id="value">'.$val.'</span>';
$>
Now you can get value using DOM, use innerHTML of span id, in this case you don't need to do any call to server, or Ajax or another thing.
Your page will print it using PHP, and you JavaScript will get value using DOM.
<?php
$val = $myService->getValue(); // Makes an API and database call
echo "
<script>
myPlugin.start({$val});
</script> ";
?>
we can do it using php heredoc:
<?php
$inPhpVar = "i am php var";
$ScriptInline = <<<JS
<script>
alert('{$inPhpVar} that used in js code');
</script>
JS;
echo $ScriptInline;
?>
PHP has no relation and behavior with browsers and in some times it makes some mistake. For example we can't set for header function to redirect to a page in a blank page. Because it has no relation with the browsers and for doing this, we should use JS .Now I'm mixing these two languages to reaching the goal.
<?php
$word = $_POST["tagTxt"];
$tag = "https://www.example.com/" . $word;
echo '<script>window.open("Location: <?php $search;?>");</script>';
?>
The goal is this code but it doesn't work. I want get a string from a first page then post it with post method and then past it to a static address for redirecting with blank target. Thanks.
I think you are trying to open a new url when the page is loaded.
So if you trying to do this check the code below.
This way you are mixing the parameters received from client, processing them and them sending back to the client.
Then you use the javascript with the window.onload function to execute the redirect page when the page is loaded with the received parameter.
<?php
$word = "1";
$tag = "www.yahoo.com/" . $word;
echo '<script text="text/javascript">window.onload = function(){window.open("'.$tag.'");} </script>';
?>
Not sure I fully understood your question, but have you tried something like this:
<?php header("Location: $search");
If you are "changing" the web page. Do not use window.open
Use window.location = 'http://www.google.com/';
in your example do this
<?php
$word = $_POST["tagTxt"];
$tag = "https://www.example.com/" . $word;
echo "<script>window.location = '$tag';</script>";
?>
(copy the code above, and it should work perfectly for what you're asking for)
I fount the way.
thanks all.
<?php
$word = $_POST["tagTxt"];
$tag = "https://www.example.com/" . $word;
echo "<script>window.open( '$tag' );</script>";
?>
I am using Simple HTML Dom Parser to scrape a script tag from a webpage and then attempting to parse certain data from said tag using preg_match_all(). However, when I print preg_match_all, no results are returned.
Below is the code I'm using:
<head>
<?php
require_once "toolkit/http.php";
require_once "toolkit/web_browser.php";
require_once "toolkit/simple_html_dom.php";
?>
</head>
<body>
<?php
$prod_url = 'http://www.domain.com/subpage.html';
$html = file_get_html($prod_url);
$script = $html->find('script', 17);
//echo $script;
preg_match_all('(?<=\d":)\w++', $script, $matches);
print_r($matches);
?>
</body>
I can see that the HTML Simple Dom code is working correctly, as I get the results I expect when echoing the $script variable. The results are:
<script type="text/javascript">
var PRODUCT_JSON = {
"Def":{
"default":202705111,
"Listing:[{
"label":"Includes",
"options":[
{label:"All", id: "884"},
{label:"None", id: "485"},
]
}],
"Lookup":{
"1":202705111,
"0":202493236
}
}
};
</script>
So, the issue appears to be with the regex I'm using in preg_match_all(). The goal of the regex is to return the two numbers, 202705 and 202493, near the end of the script tag. It may have to do with escaping the double quote or parentheses, though I've also tried preg_match_all('\(?<=\d\":\)\w++', $script, $matches); with the same result. Any ideas on what I'm doing wrong?
If you keep forgetting about delimiters, you can use T-Regx, which automatically adds delimiters.
$matches = pattern('(?<=\d":)\w++')->match($script)->all();
Evening all.
This is the first post I've made on here, so I hope I get this right.
I've looked everywhere (both on this site, and elsewhere), for a solution to an issue I'm having, but I can't find anything which sounds like my issue, yet I know logically it should be doable!
I maintain two intranet sites - one English and one Welsh. They are mirrors of each other, only the domain and site name change:
Example
http://english-site/news/item/003/170314.htm
http://welsh-site/newyddion/item/003/170314.htm
So far, I've only found this: http://www.codingforums.com/javascript-programming/8523-how-do-i-switch-pages-automatically.html
Which gave me some hope, but I can't work out how to apply it to my situation.
So, the question is this - is there a way to edit and reload the hyperlink switching out this:
english-site/news/
For this:
welsh-site/newyddion/
But keeping the rest of the link the same so the page will load with the Welsh or English equivalent of its self.
I know most modern CMS's could do this kind of thing automatically...but I'm not using a modern CMS...I'm using FrontPage...I'm certain this is possible but cant find anywhere that agrees with me!
Cheers in advance for any help anyone can offer!
FrontPage is ancient and you really shouldn't use it.
That being said, this bit of JS should do what you want:
window.location.href = "http://welsh-site/newyddion" + window.location.pathname.substring(window.location.pathname.indexOf('/', 1));
The current page's path (everything that follows the domain name) is accessible using window.location.pathname. Using indexOf('/', 1) on this gives us the position in the string (starting at 0) of the first / character (we pass 1 as the second parameter so as to ignore the starting slash). We then use substring to get everything from that character on.
Finally, we set the new URL to window.location.href, which performs a redirect.
You could possibly do this using regex, but this works just as well.
I am assuming your page has a button/link/select event which triggers which domain you want to serve from saying English or Welsh. Given this condition, you can do a simple javascript replace shown below :
if (selection === "blah blah"){
domain = "http://domainA...";
} else {
domain = "http://domainB...";
}
window.location.replace(domain);
reference
I wouldn't recommend having urls generated with javascript, but rather links on each of the page to the corresponding translated page using rel="alternative" and hreflang="code" with the language code corresponding to the 2 letter language code standard as depicted in http://googlewebmastercentral.blogspot.mx/2010/09/unifying-content-under-multilingual.html
to instruct the bots the pages are the same content in different languages.
If you could use a bit of php or server side code you could create your link reference very easily by replacing the urls with the new urls you are trying to create out of the current url. This is done by using patterns that perfectly match your criteria of url rewriting, that said, if you dont have any pattern, the best would be to set each link url separate per page.
Lets say you only need to convert english-site domain to welsh-site and news path segment to. According to http://reference.sitepoint.com/html/lang-codes, Welsh lang 2 letter standard would be 'cy'.
<?php
$lang['cy']['domain'] = 'welsh-site';
$lang['cy']['lang'] = 'Welsh';
$lang['cy']['news_slug'] = 'newyddion';
$lang['en']['domain'] = 'english-site';
$lang['en']['lang'] = 'English';
$lang['en']['news_slug'] = 'news';
$lang['default'] = 'en';
Explanation:
We are defining an array of languages where we will setup anything we need to translate. This is a multidimensional array map that defines each language by key in the first dimension, then each segment to translate in the second dimension. In this second dimansion we will setup special keys ending in _slug which will be part of the url to translate. This array can be saved in a special file apart for anything else and where we can go and edit easily without having us to modify the core code.
After defineyour initial language settings, now you need the code to identify the current language and path:
<?php
include('lang.php'); //this is the file where the language array is defined
$path = $_SERVER['REQUEST_URI'];
$host = isset($_SERVER['HTTP_HOST']) ? substr($_SERVER['HTTP_HOST'], 0, strpos($_SERVER['HTTP_HOST'], ':')) : $_SERVER['SERVER_NAME'];
foreach ($lang as $code => $l) {
if ($l['domain'] == $host) {
$current_lang = $code;
break;
}
}
if ( ! isset($current_lang)) {
$current_lang = $lang['default'];
}
$_ = $lang[$current_lang];
$segment_1 = reset(explode('/', trim($path, '/'));
foreach ($lang[$current_lang] as $section => $url_segment) {
if ($segment_1 == $url_segment && substr($section, -5) == '_slug')
$current_section = $section;
break;
}
}
Explanation:
This code works as a bridge code that obtains the current section and language. First we obtain the host (domain name) and url path. In the first loop we match against any language domain to find the correct language we are on, then in the second loop we try to find the current section we are on with respect to the current language.
Now a little code to write the links using known information :
<head>
<?php foreach ($lang as $code => $l): ?><?php if ($code != $current_lang) : ?>
<?php $lang_path = isset($current_section) ? str_replace('/' . $_[$current_section] . '/', '/' . $l[$current_section] . '/', $path) : $path; ?>
<?php $lang_url = '//' . $l['domain'] . $lang_path; ?>
<link rel="alternative" hreflang="<?php echo $code; ?>" href="<?php echo $lang_url; ?>">
<?php endif; ?><?php endforeach; ?>
</head>
Explanation:
We are adding links that will tell bots the other links in your page are just different representations of this page in a different language. We also specify the lang code inside hreflang attribute (http://googlewebmastercentral.blogspot.mx/2010/09/unifying-content-under-multilingual.html)
Then you create your links (in the body section somewhere) the exact same way:
<ul>
<?php foreach ($lang as $code => $l): ?>
<?php if ($code != $current_lang) : ?>
<?php $lang_path = isset($current_section) ? str_replace('/' . $_[$current_section] . '/', '/' . $l[$current_section] . '/', $path) : $path; ?>
<?php $lang_url = '//' . $l['domain'] . $lang_path; ?>
<li><?php echo $l['lang']; ?></li>
<?php else : ?>
<li class="active"><?php echo $l['lang']; ?></li>
<?php endif; ?>
<?php endforeach; ?>
</ul>
For all this to work your server must support PHP extension. I used php code because this is the most common code support to find.
You also need to change your file extensions, from .html to .php for this to work.
Hope it works for you. This might not be what you wanted, but rather what you actually need.