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Access javascript variables on server php file via browser javascript

using javascript code in browser to access javascript variable in server php file
( the php file search a text file and returned result as a php variable, then I set that php variable as javascript variable)
//php file on server called data.php
<?php
$search = 'bing';
// Read from file
$lines = file('text.txt');
$linea='';
foreach($lines as $line)
{
// Check if the line contains the string we're looking for, and print if it does
if(strpos($line, $search) !== false) {
$liner=explode(': ',$line);
$linea.= $liner[1];
}
}
echo 'Search returned: '. $linea;
<script type=\"text/javascript\">
var varxxx = $linea;
</script>
?>
//text file on server
foo: bar
el: macho
bing: bong
cake color: blue berry
mayo: ello
//Java script code in browser.
var xhr = new XMLHttpRequest();
xhr.open("GET","http://.........data.php",false);
xhr.send(null);
$Variables.setValue(5, 'varxxx');
I got
reference error
x is not defined
if I just run http://.........data.php , it shows Search returned:"Bong"
it means data.php successfully returned the result, and php $linea is Bong.
so this part below in the php file is what causes the error?
<script type=\"text/javascript\">
var varxxx = $linea;
</script>
or something wrong with my Javascript code in browser?
Any help is appreciated
Thanks in advance

Try "echoing" the script tag to the .html body.
You're getting this error because the variable is being created on the server side only, thats why the variable is not defined. Also I recomend you to use let instead of var, let is more secure in terms of scope.
//php file on server called data.php
<?php
$search = 'bing';
// Read from file
$lines = file('text.txt');
$linea='';
foreach($lines as $line)
{
// Check if the line contains the string we're looking for, and print if it does
if(strpos($line, $search) !== false) {
$liner=explode(': ',$line);
$linea.= $liner[1];
}
}
echo 'Search returned: '. $linea;
?>
// New script
<?php
echo("<script> var varxxx = ".$linea." </script>")
?>

use var from function.php file into scripts.js file

I have a function.php code simple one:
$var = "7000";
and I have another file script.js:
var Price = <?php echo $var ?>;
now it works when this code in the same file.
but when I separate the files its doesn't.
any suggestions?

As pointed out by GrumpyCrouton in his comment to you, variables out of one file can be read in another by including them
<?php
include('file1.php'); // include the file where the variable is defined
<script>
var Price = <?= json_encode($var) ?>; // in javascript code export the variable to js usign json
</script>
It is always safe to use json_encode and dump the variable directly into js no need to encapsulate it any more then that, I would add a semicolon at the end but that is more of a personal preference in this day and age.

Create a script called price.php with the following content:
<?php
header("Content-type: text/javascript"); // As suggested by Mark Eriksson
$var = "7000";
?>
const PRICE = <?php echo $var; ?>;
Now you can reference this JavaScript block on any HTML page:
<script src="price.php"></script>
You will have a global JavaScript variable (constant) called PRICE.
Do you need variable prices? No problem, you can pass a value as a parameter, for example:
<script src="price.php?price=8500"></script>
And in your price.php, you change it to:
<?php
$var = $_GET["price"];
?>
const PRICE = <?php echo $var; ?>;
Your HTML page still gets a constant named PRICE.

Well, if you want to access some PHP variables, then you need to use AJAX.
Its quite simple.
Do this inside function.php file
<?php
$var = "7000";
// Put your price into array to form it into JSON format further
$data = ["price" => $var];
return json_encode($data);
And following in your JS file.
let xhr = new XmlHttpRequest();
xhr.open('get', 'function.php', true);
xhr.onload = function() {
if (this.status == 200) {
var data = JSON.parse(this.response);
// Your final result
var Price = data.price;
}
}
xhr.send();

'unexpected token: identifier error' - assigning php json array type variable value to a javascript function from php code

I am trying to call JavaScript function in php and pass it value of a php json array type variable as an argument. I found from search on SO forum one way to do this is to echo/print_r the variable value to a js var inside a js script within php code. I am trying do it this way but I am not able to recover from 'unexpected token: identifier error ' while doing so.
I am trying to figure out the reason of syntax error but couldn't. I tried different ways what I found; by putting quotes single/double around php part within the script, without quotes as some places I found solution with quotes some places without but no one seems working.
Here is my code. It will be very helpful if someone sees it and point what is causing this error.
<script>
dspChrt(WData);
.......
</script>
<HTML>
<?php
$WData;
require("Connection.php");
try {
$stmt = $conn->prepare("Select humidity, temperature FROM weatherdata");
$stmt->execute();
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
foreach($stmt->fetchAll() as $k=>$v) {
$WData = json_encode($v);
//print_r($WData);
}?>
<script>
var Wdata = <?php print_r($WData);?>
dspChrt(WData);
consol.log(WData);
</script>
<?php
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}
?>
</HTML>

First of all you need to parse the JSON using JSON.parse.
Also you need to change the sequence of php and javascript code.
If you want to assign php data to Javascript variable, please retrieve data using php first and write javascript code below it.
For example :
<?php
$v = array(1,2,3);
$data = json_encode($v);
?>
<script>
var WData = JSON.parse('<?php echo $data; ?>');
dspChrt(WData);
</script>

You should encode your PHP into JSON to pass it to JavaScript.
And you should prepare your data first.
<?php
$data = array('xxx'=>'yyy');
?>
<script>
var data = <?php echo json_encode($data); ?>;
//then in js, use the data
</script>
for your code, there are too many errors to be fixed:
<HTML>
<?php
require("Connection.php");
$stmt = $conn->prepare("Select humidity, temperature FROM weatherdata");
$stmt->execute();
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
$WData = array();
foreach($stmt->fetchAll() as $k=>$v) {
$WData[] = $v;
}
?>
<script>
var WData = <?php echo json_encode($WData);?>;
console.log(WData);
dspChrt(WData);
</script>
</HTML>

How to create alert function in php?

i want insert user in db mysql, i have a controller php, im validate if user exist in db through a function, then if or not exist i want show alert function an redirect to php page, for that im using:
<?php
if(dao::existUser($user)) {
echo "<script type=\"text/javascript\">\n";
echo "alert('user exist!');\n";
echo "window.location = ('../insertUser.php');\n";
echo "</script>";
}
this function works!! but
i want to encapsulate the function in a method to later call it
example:
<?php
class Utils {
static function responseText($message, $url) {
echo "<script type=\"text/javascript\">\n";
echo "alert('"+$message+"');\n";
echo "window.location = ('"+$url+"');\n";
echo "</script>";
}
}
then, in my controller:
<?php
if(dao::existUser($user)) {
Utils::responseText("user exist",'../insertUser.php');
}
but not work, and after call responseText, my page goes blank

I don't know what is wrong ( likely a quoting issue ), but I would suggest using a HEREDOC style for this and return the text not output the HTML from the class by itself. Latter it could be hard to track where this output is coming from by looking just in the class that calls it. By doing echo Utills::.. you'll be able to easily see it's outputting something, whiteout having to look into what the class does.
So like this.
<?php
class Utils {
static function responseText($message, $url) {
return <<<HTML
<script type="text/javascript">
alert('$message');
window.location = '$url';
</script>
HTML; //nothing can go here no space ( before or after ) and not even this comment, nothing but HTML; litterally
}
}
echo Utils::responseText("user exist",'../insertUser.php');
HEREDOCs are a way of doing a text block without using any quotes, beware of the note i put in comments... In this case it makes the Javascript string so much more simple when you don't have to manage quote usage.
Another suggestion for this class if it is to be a collection of static methods, you can make it where it can't be instantiated ( created using new class() ) Like this
<?php
class Utils {
private function __construct(){} //no instantion
private function __clone(){} //no cloning
This way you don't accidentally do $U = new Utils(); $U->responseText(..) It's a little thing but it will insure all the methods of this class stay static. It's just a design thing I like to do, on singletons and static classes
UPDATE your issue is you are using the + to concat in PHP where you should be using the . The + is good for Javascript not so much for PHP
And the way you have it with " double quotes concat is unnecessary, instead of
echo "alert('"+$message+"');\n";
Try
echo "alert('$message');\n";

If i understand you properly bind javascript to php.
<?php
$script = '<script type="text/javascript">';
$script .= 'function showAlert(){';
$script .= 'alert("Hello World.");';
$script .= '}';
$script .= '</script>';
echo $script;
?>
Than after page has loaded you can call it !
<script type="text/javascript">
window.onload = function () {
showAlert();
}
</script>

How to pass var to include file and then use this var in include file using php , javascript?

How to pass var to include file (test.php) and then use this var in include file (test.php) ?
First i want to declare var in main.php and then i want to pass this var to test.php and use this var in test.php (EG: echo , if..else)
I try with php and javascript but not work both , Could you please give me some advice ?
using PHP
main.php
<?php
include('test.php');
$number = '555';
test($number);
?>
test.php
<?php
function test($numeric)
{
return $sample = $numeric;
}
echo test($number);
?>
Using JS
main.php
<?php
include('test.php');
$number = '555';
?>
<script type="text/javascript">
doCallAjax();
</script>
test.php
<script type="text/javascript">
function doCallAjax() {
var number = "<?PHP echo $number; ?>";
alert(number);
}
</script>

if you want to share your data on multiple php files, consider to use the global variable or session, so it will be something like this:
SESSION:
main.php:
$_SESSION['number'] = '555';
test.php:
echo $_SESSION['number'];
GLOBAL VARIABLES:
main.php
global $number;
$number = '555';
test.php
global $number;
echo $number;