URL Redirect in a Loop - javascript

I am using a java script in php to redirect a URL. This works for me because each time the loop is run, the link opens in a new window and the desired action takes place. However I want to stop the script from opening new windows and run / load within the same page. If I open the link the same page, it redirects to the new page in the first run and the loop does not run further.
I have no control over the next pages as they are part of an API. I do not actually want to navigate to the new page(s) but I just want to run the http:// API, which may even run in the background or something.
Please advise on what would be the best method to handle this ?
This is my current script:
<?php
$x1=$_POST["textfield1"];
$msg = "New Message Alert From $x1. blah blah";
$query = "SELECT * FROM phone_list";
$result = mysql_query($query);
$num=mysql_numrows($result);
$i=0;
while ($i < $num)
{
$f1=mysql_result($result,$i,"phone");
echo'<script> window.open("http://linktonextpage&msg='.$msg.'&num='.$f1'"); </script>';
$i++;
}
?>
Thanks in Advance !

As you're discovering, once you move from one page to another at that point the previous page is gone from the browser. JavaScript won't continue to run from pages that are no longer loaded.
I do not actually want to navigate to the new page(s) but I just want to run the http:// API, which may even run in the background or something.
Then don't navigate to the page. Instead, make an AJAX request to the desired URL. Something as simple as this:
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
// This function is called when the AJAX request completes.
// Here you would check for errors or respond in some way, if needed.
};
xhttp.open('GET', 'http://someurl', true);
xhttp.send();
As long as you're not making too many concurrent requests, you can run that in a loop. Just enclose it in a function:
function sendRequest(url) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
// This function is called when the AJAX request completes.
// Here you would check for errors or respond in some way, if needed.
};
xhttp.open('GET', url, true);
xhttp.send();
}
And call that function in a loop over your urls:
for (var i = 0; i < myUrls.length; i++) {
sendRequest(url);
}
You can get a lot fancier with this pretty easily, passing the callback function into the sendRequest() function or having sendRequest() return the AJAX promise or lots of other things. It's up to you what further features you want to add. The main point here, in response to your statement above, is simply to make AJAX requests in the background rather than navigate the browser to the URLs.
Note: Currently your loop is server-side, which is emitting a lot of repeated code to the browser. You can probably just emit the JSON-encoded values and perform the loop client-side as demonstrated above. Or, if you really want to loop server-side, then just define a function like the one above and emit calls to that function in a loop. It's still a lot of repeated client-side code, but it'll get the job done.

Another solution - less correct than solution with AJAX,
but very simple:
You can add iframes instead of opening popups.
while(...){
echo '<iframe src="http://linktonextpage&msg='.$msg.'&num='.$f1'." width="100%" height="120"></iframe>';
}

In your code it seems like you want to send messages to all the numbers fetched from database so if you want to use JavaScript you can do as previous answer.
Another way of doing the same is without using JavaScript.
You can also make Curl request to the Api Urls. Within your PHP code without loading the page.
While (condition) { $service_url = 'http://linktonextpage&msg='.$msg.'&num='.$f1'';
$curl = curl_init($service_url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
$curl_response = curl_exec($curl);
curl_close($curl);}

Related

I'm trying to make a website load forever. How can I do this?

I'm trying to make a website load forever. My current idea is to request a PHP file:
<?php
sleep(30);
This will delay the load by 30 seconds, which a quick Google search tells me should be within most browsers' timeouts. I was thinking of writing some JavaScript to append a new link tag after a bit less than 30 seconds to keep the page loading, but I found that this didn't keep the loading icon spinning (with Chrome at least):
window.addEventListener( 'load', () => {
var i = 0;
setInterval( () => {
i++;
var newScript = document.createElement('script');
newScript.src = 'infinite-loading.php?i=' + i;
document.querySelector('#infinite-loading').after(newScript);
console.log('The deed is done');
}, 25000)
} )
<script id="infinite-loading" src="infinite-loading.php"></script>
The code above appends a script tag every 25 seconds, and the browser loads the PHP file each time, but it doesn't show the loading icon. I added the URL parameter because I wasn't sure if browsers would cache the page.
I also want to make sure that the server with the PHP file won't be overloaded. I'm not sure if many sleep() functions running constantly at the same time will cause any issues.
Is there a better way to do this client-side? Should I use something other than PHP? Something multi-threaded?
(Edit: Sorry for the awkward title, Stack Overflow didn't like my first one.)
You need that browser will continue reading your page forever (I'm talking about HTML, not other linked objects). So you need not to break timeout and feed some data from backend to frontend.
Example of sending portion of data to client:
ob_end_flush();
# CODE THAT NEEDS IMMEDIATE FLUSHING
ob_start();
Now we need to understand the minimum data packet size that is expected by the browser. Minimal googling tells us a limit of 8-10 bytes.
So combining this together we can try to check (I did not checked, it is just my version):
<?php
while (true) {
sleep(25);
ob_end_flush();
echo " "; // 10 spaces...
ob_start();
}
Not sure why you would want to do anything like this but the simplest solution I think is an endless loop.
<?php
while(true)
{
}

Javascript on webpage not changing text

I have the following script at the bottom of my php page, it runs on pageload, but I need it running every 10 seconds. It only runs on page load.
PHP is running.
I've tested this with a countdown from ten, and the script is actually looping, but for some reason not when i integrate this PHP.
Please help.
<script>
var CurrentBranch = "<?php echo file_get_contents('gitstatus.txt'); ?>";
var x = setInterval(function () {
CurrentBranch = "<?php echo file_get_contents('gitstatus.txt'); ?>";
document.getElementById("CurrentTestBranch").innerHTML = CurrentBranch;
CurrentBranch = "";
}, 10000);
</script>
Edit:
The code does display the file contents the first time around. But does not refresh when I make a change and save it.
Your PHP code is run only when the page loads. It generates string literals when it runs. These do not get updated when the interval function gets called repeatedly (because the PHP does not run again).
If you want to get new data from PHP you need to make new HTTP requests.
You could either reload the entire page, or use XMLHttpRequest (or fetch) to call a web service that gives you the data you want (Ajax is a useful search term).
PHP happens before HTML hits the server.
Look up setTimeout() javascript command. What you need to do is get javascript to call another php script, which checks and echoes your value.
Something like this (could be pseudocode, from memory):
setTimeout(function(){
var CurrentBranch = $.get('/url/that/sends/value');
// do something with your value, call a function, whatever
}, 10000);

call PHP function inside JS [duplicate]

Is there a way I can run a php function through a JS function?
something like this:
<script type="text/javascript">
function test(){
document.getElementById("php_code").innerHTML="<?php
query("hello"); ?>";
}
</script>
<a href="#" style="display:block; color:#000033; font-family:Tahoma; font-size:12px;"
onclick="test(); return false;"> test </a>
<span id="php_code"> </span>
I basically want to run the php function query("hello"), when I click on the href called "Test" which would call the php function.
This is, in essence, what AJAX is for. Your page loads, and you add an event to an element. When the user causes the event to be triggered, say by clicking something, your Javascript uses the XMLHttpRequest object to send a request to a server.
After the server responds (presumably with output), another Javascript function/event gives you a place to work with that output, including simply sticking it into the page like any other piece of HTML.
You can do it "by hand" with plain Javascript , or you can use jQuery. Depending on the size of your project and particular situation, it may be more simple to just use plain Javascript .
Plain Javascript
In this very basic example, we send a request to myAjax.php when the user clicks a link. The server will generate some content, in this case "hello world!". We will put into the HTML element with the id output.
The javascript
// handles the click event for link 1, sends the query
function getOutput() {
getRequest(
'myAjax.php', // URL for the PHP file
drawOutput, // handle successful request
drawError // handle error
);
return false;
}
// handles drawing an error message
function drawError() {
var container = document.getElementById('output');
container.innerHTML = 'Bummer: there was an error!';
}
// handles the response, adds the html
function drawOutput(responseText) {
var container = document.getElementById('output');
container.innerHTML = responseText;
}
// helper function for cross-browser request object
function getRequest(url, success, error) {
var req = false;
try{
// most browsers
req = new XMLHttpRequest();
} catch (e){
// IE
try{
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch(e) {
// try an older version
try{
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch(e) {
return false;
}
}
}
if (!req) return false;
if (typeof success != 'function') success = function () {};
if (typeof error!= 'function') error = function () {};
req.onreadystatechange = function(){
if(req.readyState == 4) {
return req.status === 200 ?
success(req.responseText) : error(req.status);
}
}
req.open("GET", url, true);
req.send(null);
return req;
}
The HTML
test
<div id="output">waiting for action</div>
The PHP
// file myAjax.php
<?php
echo 'hello world!';
?>
Try it out: http://jsfiddle.net/GRMule/m8CTk/
With a javascript library (jQuery et al)
Arguably, that is a lot of Javascript code. You can shorten that up by tightening the blocks or using more terse logic operators, of course, but there's still a lot going on there. If you plan on doing a lot of this type of thing on your project, you might be better off with a javascript library.
Using the same HTML and PHP from above, this is your entire script (with jQuery included on the page). I've tightened up the code a little to be more consistent with jQuery's general style, but you get the idea:
// handles the click event, sends the query
function getOutput() {
$.ajax({
url:'myAjax.php',
complete: function (response) {
$('#output').html(response.responseText);
},
error: function () {
$('#output').html('Bummer: there was an error!');
}
});
return false;
}
Try it out: http://jsfiddle.net/GRMule/WQXXT/
Don't rush out for jQuery just yet: adding any library is still adding hundreds or thousands of lines of code to your project just as surely as if you had written them. Inside the jQuery library file, you'll find similar code to that in the first example, plus a whole lot more. That may be a good thing, it may not. Plan, and consider your project's current size and future possibility for expansion and the target environment or platform.
If this is all you need to do, write the plain javascript once and you're done.
Documentation
AJAX on MDN - https://developer.mozilla.org/en/ajax
XMLHttpRequest on MDN - https://developer.mozilla.org/en/XMLHttpRequest
XMLHttpRequest on MSDN - http://msdn.microsoft.com/en-us/library/ie/ms535874%28v=vs.85%29.aspx
jQuery - http://jquery.com/download/
jQuery.ajax - http://api.jquery.com/jQuery.ajax/
PHP is evaluated at the server; javascript is evaluated at the client/browser, thus you can't call a PHP function from javascript directly. But you can issue an HTTP request to the server that will activate a PHP function, with AJAX.
The only way to execute PHP from JS is AJAX.
You can send data to server (for eg, GET /ajax.php?do=someFunction)
then in ajax.php you write:
function someFunction() {
echo 'Answer';
}
if ($_GET['do'] === "someFunction") {
someFunction();
}
and then, catch the answer with JS (i'm using jQuery for making AJAX requests)
Probably you'll need some format of answer. See JSON or XML, but JSON is easy to use with JavaScript. In PHP you can use function json_encode($array); which gets array as argument.
I recently published a jQuery plugin which allows you to make PHP function calls in various ways: https://github.com/Xaxis/jquery.php
Simple example usage:
// Both .end() and .data() return data to variables
var strLenA = P.strlen('some string').end();
var strLenB = P.strlen('another string').end();
var totalStrLen = strLenA + strLenB;
console.log( totalStrLen ); // 25
// .data Returns data in an array
var data1 = P.crypt("Some Crypt String").data();
console.log( data1 ); // ["$1$Tk1b01rk$shTKSqDslatUSRV3WdlnI/"]
I have a way to make a Javascript call to a PHP function written on the page (client-side script). The PHP part 'to be executed' only occurs on the server-side on load or refreshing'. You avoid 'some' server-side resources. So, manipulating the DOM:
<?PHP
echo "You have executed the PHP function 'after loading o refreshing the page<br>";
echo "<i><br>The server programmatically, after accessing the command line resources on the server-side, copied the 'Old Content' from the 'text.txt' file and then changed 'Old Content' to 'New Content'. Finally sent the data to the browser.<br><br>But If you execute the PHP function n times your page always displays 'Old Content' n times, even though the file content is always 'New Content', which is demonstrated (proof 1) by running the 'cat texto.txt' command in your shell. Displaying this text on the client side proves (proof 2) that the browser executed the PHP function 'overflying' the PHP server-side instructions, and this is because the browser engine has restricted, unobtrusively, the execution of scripts on the client-side command line.<br><br>So, the server responds only by loading or refreshing the page, and after an Ajax call function or a PHP call via an HTML form. The rest happens on the client-side, presumably through some form of 'RAM-caching</i>'.<br><br>";
function myPhp(){
echo"The page says: Hello world!<br>";
echo "The page says that the Server '<b>said</b>': <br>1. ";
echo exec('echo $(cat texto.txt);echo "Hello world! (New content)" > texto.txt');echo "<br>";
echo "2. I have changed 'Old content' to '";
echo exec('echo $(cat texto.txt)');echo ".<br><br>";
echo "Proofs 1 and 2 say that if you want to make a new request to the server, you can do: 1. reload the page, 2. refresh the page, 3. make a call through an HTML form and PHP code, or 4. do a call through Ajax.<br><br>";
}
?>
<div id="mainx"></div>
<script>
function callPhp(){
var tagDiv1 = document.createElement("div");
tagDiv1.id = 'contentx';
tagDiv1.innerHTML = "<?php myPhp(); ?>";
document.getElementById("mainx").appendChild(tagDiv1);
}
</script>
<input type="button" value="CallPHP" onclick="callPhp()">
Note: The texto.txt file has the content 'Hello world! (Old content).
The 'fact' is that whenever I click the 'CallPhp' button I get the message 'Hello world!' printed on my page. Therefore, a server-side script is not always required to execute a PHP function via Javascript.
But the execution of the bash commands only happens while the page is loading or refreshing, never because of that kind of Javascript apparent-call raised before. Once the page is loaded, the execution of bash scripts requires a true-call (PHP, Ajax) to a server-side PHP resource.
So, If you don't want the user to know what commands are running on the server:
You 'should' use the execution of the commands indirectly through a PHP script on the server-side (PHP-form, or Ajax on the client-side).
Otherwise:
If the output of commands on the server-side is not delayed:
You 'can' use the execution of the commands directly from the page (less 'cognitive' resources—less PHP and more Bash—and less code, less time, usually easier, and more comfortable if you know the bash language).
Otherwise:
You 'must' use Ajax.

Eternal Ajax Returns Nothing, No PHP/Javascript errors, syntax or otherwise

Note: I am aware that json/jquery appears to be the preferred way of doing things at the moment. Nevertheless, I am using just plain old ajax without json/jquery.
I have set my website up so that there are no php calls in the index page. Instead, I load scripts which handle most link clicks via ajax calls back to the server. Theoretically, the server returns the response text, and then the javascript on readystatechange function (set to ajax_response()) inserts the response text directly into the div container with id="innercontent".
Here is the code for my main javascript file:
function ajax()
{
try{ var request = new XMLHttpRequest()}
catch(e1){
try{ request = new ActiveXObject("Msxml2.XMLHTTP") }
catch(e2){
try{ request = new ActiveXObject("Microsoft.XMLHTTP") }
catch(e3){ request = false }
}
} return request
}
function ajax_response()
{
if(this.readyState == 4){
if(this.status == 200){
if(this.responseText != null){
document.getElementById('innercontent').innerHTML = this.responseText
} else alert("Ajax error: No data received")
} else alert("Ajax error: " + this.statusText)
}
}
function fetch_document(opcode)
{
params = "opcode=" + opcode
request = new ajax();
request.open("POST", "/site-php/fetch_document.php", true)
// request.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
// request.setRequestHeader("Content-length", params.length)
request.setRequestHeader("Connection", "close")
request.onreadystatechange = ajax_response()
request.send(params)
}
function fetch_comic(series, page_number)
{
params = "series=" + series + "&page_number=" + page_number
request = new ajax();
request.open("POST", "/site-php/fetch_comic.php", true)
// request.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
// request.setRequestHeader("Content-length", params.length)
request.setRequestHeader("Connection", "close")
request.onreadystatechange = ajax_response()
request.send(params)
}
There doesn't appear to be any syntax errors in the javascript, so I thought maybe that the problem was on the server side. But no errors are logged in /var/log/error_log.
Here is the code for my php functions:
<?php
require_once "kolodruid.php";
require_once "login.php";
if(isset($_POST['series']) && isset($_POST['page_number'])){
$series = $_POST['series'];
$page_number = $_POST['page_number'];
}
$mysql_db = mysql_connect($mysql_host, $mysql_user, $mysql_pass);
mysql_select_db("webcomics");
mysql_close($mysql_db);
$fd = $docroot . "test.html";
$msg = file_get_contents($fd);
echo $msg;
?>
Note that the actual functionality of this function is to fetch webcomic information from a database. In the process of trying to figure out what has gone wrong, however, I ended up simplifying the function to try to see if just a simple echo statement would work.
also:
<?php
require_once "kolodruid.php";
$opcode = $_POST['opcode'];
switch($opcode){
case "ABOUT":
echo file_get_contents("about.html");
break;
default:
echo file_get_contents("whoops.html");
break;
}
?>
When I look at the firefox console network tab, clicking on the links "webcomic" generates green lights all the way. I check to see if the parameters tab has any data, and it does. The response tab, however, doesn't contain anything.
I've checked that all the files are reachable and in places that the server has access to. I also took out the setrequestheader() functions in the javascript, as it seems that was causing a fatal error. I then re-enabld the close connection setrequestheader() to see if maybe I actually still had to set that one manually. It seems that it didn't generate a fatal error, so I didn't comment it back out.
I've checked the php code for syntax errors, and also checked the javascript code for syntax errors. Both come out clean. I've restarted my server several times (it's localhost), and have also restarted my mysql database server out of desperation.
At this point, the whole enterprise had devolved into just making minor edits in the desperate hope that SOMETHING gives a clue as to what is going on. I have changed the asynchronous calls to synchronous calls to see if that maybe was the problem, but to no avail. (Thus, I rechanged them back to asynchronous calls).
I feel like it's something really stupid and/or obvious, but I've been pouring over the code for hours, and am afraid I can't see the forest for the trees by now. Please help!
Thank you for reading this. I'm aware that Javascript questions are pretty common, but I've been reading question and answer sites for hours, too. D:
In case it matters, I'm using Apache version 2.4.6
Thank you for you help!
It turned out to be something mind-blowingly obvious after all. I was calling the function ajax_response() and assigning the value to onreadystatechange. Removing the parenthesis after ajax_response produced the desired behavior.

Multiple xhr onload

I have this simple code for get elements from a external source
for(var i=0; i<10; i++)
loadPage(link[i]);
function loadPage(href)
{
var ajax = new XMLHttpRequest();
ajax.open('get',href);
ajax.responseType = 'document';
ajax.onreadystatechange=function()
{
console.log(ajax.responseXML.querySelectorAll("a[href^='magnet']")[0].getAttribute("href"));
}
ajax.send();
}
but when i read the console i get only 2 or 3 result instead of 10. i think is because i can't run multiple onload. How i can fix this?
By onload, you mean multiple ajax.send? that is likely not the problem.
Could is simply be that the returned ajax isn't returning something that matches your selector (magnet) or that your server doesn't answer properly to all requests? replace your console.log with a simple console.log ("Here be dragons");
If you ajax fetch pages from the same server, you should check the logs see how many requests do you have, and if you always reply correctly. Some servers will return at 50x error when too many requests in parallel, or put a breakpoint in your loadPage function, the pause is going to be enough to let the server process everything in time.

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