Access a JavaScript Variable from PHP

How to get JavaScript variable value in PHP

You will need to use JS to send the URL back with a variable in it such as:
http://www.site.com/index.php?uid=1

by using something like this in JS:

window.location.href=”index.php?uid=1";

Then in the PHP code use $_GET:

$somevar = $_GET["uid"]; //puts the uid varialbe into $somevar

Access a JavaScript variable from PHP

The short answer is you can't.

I don't know any PHP syntax, but what I can tell you is that PHP is executed on the server and JavaScript is executed on the client (on the browser).

You're doing a $_GET, which is used to retrieve form values:

The built-in $_GET function is used to collect values in a form with method="get".

In other words, if on your page you had:

<form method="get" action="blah.php">
    <input name="test"></input>
</form>

Your $_GET call would retrieve the value in that input field.

So how to retrieve a value from JavaScript?

Well, you could stick the javascript value in a hidden form field...

<script type="text/javascript" charset="utf-8">
    var test = "tester";
    // find the 'test' input element and set its value to the above variable
    document.getElementByID("test").value = test;
</script>

... elsewhere on your page ...

<form method="get" action="blah.php">
    <input id="test" name="test" visibility="hidden"></input>
    <input type="submit" value="Click me!"></input>
</form>

Then, when the user clicks your submit button, he/she will be issuing a "GET" request to blah.php, sending along the value in 'test'.

Get Javascript Variable value in PHP variable

use this code for use variable

  <?php
  session_start();
  echo $_SESSION['php_value'];
  ?>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
  <script>
    function getValue(obj){
    var value = obj.value;
    $.ajax({
        type:"POST",
        url: 'edit.php',
        data: "val="+ value,
        dataType: 'text',
        async: false,
        cache: false,
        success: function ( result )  {
            window.location.reload();
        }
    });
}

</script>

<select onchange="getValue(this)">
<option value="1" <?php if($_SESSION['php_value'] == 1) echo 'selected';?>>One</option>
<option value="2" <?php if($_SESSION['php_value'] == 2) echo 'selected';?>>Two</option>
<option value="3" <?php if($_SESSION['php_value'] == 3) echo 'selected';?>>Three</option>
<option value="4" <?php if($_SESSION['php_value'] == 4) echo 'selected';?>>four</option>

</select>

then create edit.php file

<?php
 session_start();
 $_SESSION['php_value'] = $_REQUEST['val'];
?>

Use javascript variable in php code

You can't use javascript variable in php code. Php code run's on the serverside and javascript code runs in the client side. You can't ask the browser to run php code.

Your variable loc will have a value only when the code reaches the browser.

If you want to get some value from server and combine it with javascript variables then do the following.

Use an ajax request and send the desired values to server. The server will return with a response. Use that response text and store it in your action variable.

How to access PHP variable in JavaScript code?

You can access a PHP variable inside javascript by echoing it within quotes if the value is a string and just need to echo if it is an integer, like;

var i=<?php echo $i; ?>;

How do I pass JavaScript variables to PHP?

You cannot pass variable values from the current page JavaScript code to the current page PHP code... PHP code runs at the server side, and it doesn't know anything about what is going on on the client side.

You need to pass variables to PHP code from the HTML form using another mechanism, such as submitting the form using the GET or POST methods.

<DOCTYPE html>
<html>
  <head>
    <title>My Test Form</title>
  </head>

  <body>
    <form method="POST">
      <p>Please, choose the salary id to proceed result:</p>
      <p>
        <label for="salarieids">SalarieID:</label>
        <?php
          $query = "SELECT * FROM salarie";
          $result = mysql_query($query);
          if ($result) :
        ?>
        <select id="salarieids" name="salarieid">
          <?php
            while ($row = mysql_fetch_assoc($result)) {
              echo '<option value="', $row['salaried'], '">', $row['salaried'], '</option>'; //between <option></option> tags you can output something more human-friendly (like $row['name'], if table "salaried" have one)
            }
          ?>
        </select>
        <?php endif ?>
      </p>
      <p>
        <input type="submit" value="Sumbit my choice"/>
      </p>
    </form>

    <?php if isset($_POST['salaried']) : ?>
      <?php
        $query = "SELECT * FROM salarie WHERE salarieid = " . $_POST['salarieid'];
        $result = mysql_query($query);
        if ($result) :
      ?>
        <table>
          <?php
            while ($row = mysql_fetch_assoc($result)) {
              echo '<tr>';
              echo '<td>', $row['salaried'], '</td><td>', $row['bla-bla-bla'], '</td>' ...; // and others
              echo '</tr>';
            }
          ?>
        </table>
      <?php endif?>
    <?php endif ?>
  </body>
</html>

How I can use the Javascript variable in PHP?

You can't access javascript variables using PHP as JavaScript is executed on client side ( browser ) and PHP on server side.

The best what you can do is send data from those variables as request to server and read them, for example using jQuery ajax request:

Good example you can find here:
jQuery Ajax POST example with PHP

Or you can use this:

javascript

function sendData(variable1, variable2) {
    $.ajax({
        type: 'post',
        url: 'myphpscript.php'
        data: 'var1='+variable1+'&var2='+variable2
    });

myphpscript.php

<?php
$variable1 = $_POST['var1'];
$variable2 = $_POST['var2'];