PHP inside a JAVASCRIPT function

[zeberdeee]

I know PHP is server side and JS is browser.
Is it possibe to put php code inside a javascript function.
ie
body <onUnload="finish();">

<script="javascript">
function finish() {
<?php
UNSET($_SESSION['foo'])
?>
</script>

as you can see from the php i am altering a session variable(the session was started at the head of the page, obviously)

So 2 questions really if php can be executed in javascript functions can the $_SESSION vars be altered or would this require another session_start() because headers have been sent??

when i have tested this, the PHP code seems to always be execued when the page is loaded?? so my SESSION var is cleared? and it actually damages other vars in the $_SESSION??

if it does work i could use this further to know when someone has logged off perhaps and delete then from files?

[insane]

The PHP Code is always executed, whether the javascript function is being called or not. Javascript behaves like HTML in this case... you can't make PHP-Code depending on conditions set by HTML Code.

What you can do ,though, is altering the Javascript - code under conditions set by PHP. So, for example you can define a javascript function like this:

<script language="JavaScript">
function readfromDB()
{
  <?php 
     if($MySQL)
         echo $MySQL_JavaScript_Command;
     elseif($PostGreSQL)
         echo $PostGreSQL_JavaScript_Command;
   ?> 
}
</script>

[zeberdeee]

not sure what you mean by if($mysql);
but you say any php code in a javascript function will be executed on page load, i get that.
but the php will get executed again when the javascript function is called ?
if so i need to have a condition in the PHP that will not be true when page originally loads but will be true when the javascript function is called!!

like in a form with a hidden variable if($firstpass) { // ect

[ereptur]

In your example the php would be executed before it ever reaches the browser. This is what you code results in by the time it hits the browser.

body <onUnload="finish();"> 

<script="javascript"> 
function finish() { 
}
</script> 

[insane]

My example wasn't the best i admit.

The PHP Code will not be executed again, when the Javascript function is called!

What I tried to explain was, that you can "write" Javascript functions with PHP. You can put some strings into PHP-Variables and echo them in your Javascript function so that the function will do different things when PHP-variables are defined different.

You cannot execute PHP-Code in runtime by executing a JavaScript function.