php - JavaScript code in source doesn't reflect code that is actually executed

Question

My javascript code appears to work as it's supposed to. However, when I 'view source' in Chrome, it disagrees with the javascript that is actually executed.

Here is my code:

<?php
    $_SESSION['new'] = "blue";
    if (!isset($_SESSION['old'])) { $_SESSION['old'] = "blue"; }
        echo '<script type="text/javascript">
            $(document).ready(function() {
                changeCol("'.$_SESSION["old"].'","'.$_SESSION["new"].'");
            });
          </script>';
    $_SESSION['old'] = "blue";
?>    

$_SESSION['old']="green" from the previous page. The code is supposed to call changeCol("green","blue"), and then set $_SESSION['old']="blue".

In fact, both of these things happen, so my code works as it's designed, but if I view source, it says changeCol("blue","blue"). This is strange, because if in changeCol() I write the passed variables to console.log, I get green, blue.

So if it's calling changeCol(green,blue) why does it say changeCol(blue,blue) when I view source?

Answer 1

When you view the source, you're probably making an additional request. Your session variable will be reset.

If you're using Chrome or Firefox —?which you should be —?you can open up either the Web Developer Tools or Firebug and examine the actual DOM tree. (This is also pretty useful in situations where a script has added content dynamically.)