PHP/AJAX check if session variable changed

Question

Greetings!

I need to dynamically check if a session variable changes every few seconds. For example, the PHP session variable "x" may have a value of "1", and then after five seconds, has a value of "2".

The PHP session variable "x" is changed by using a form. If the session variable changes, I need the page to reload.

How can I reload the page if the session variable changes without refreshing the page manually?

Answer 1

AJAX is a good solution for something like this. Just make a request to script that will return the current value for the session variable. If it is different, then reload.

So, when your page first loads, you have something like

NOTE: This example is relying on jquery library.

<script type="text/javascript">
    var currentSessionValue = <?php echo $_SESSION['something']; ?>;
    // pseudo code
    setTimeout(checkVariableValue, 5000);
    function checkVariableValue() {
         $.ajax({
            url: 'checkMyValue.php',
            success: function(newVal) {
                if (newVal != currentSessionValue);
                    currentSessionValue = newVal;
                    alert('Value Has Changed.');
                    doSomethingDifferent_or_refreshPage();
                }
         });
    }
</script>

checkMyValue.php

<?php
     start_session();
     echo $_SESSION['myVariable'];
?>