从javascript，onload调用php函数（AJAX？）

Question

I have been searching for almost an hour without finding proper example to fix my problem: I would like to call a PHP function (it's a simple unlink with the path given from a javascript function that's executed on page load). I am not good at all with AJAX and I would like to understand how to call directly the PHP function, contained in the index.php file, from the javascript code.

Here's what I have in my javascript code snippet:

var xmlhttp;

if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","/dev/templates/absolu/index.php?s=" + Math.random(),true);
//@unlink(listeImages[i].toString());

Answer 1

You send the function name (in case you will have more functions in the future) and params as get params

var fileToDelete;
var xmlhttp;

    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp=new XMLHttpRequest();
    }
    else
    {// code for IE6, IE5
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.open("GET","/dev/templates/absolu/index.php?s=" + Math.random()+"&action=delete&file="+fileToDelete,true);

On your PHP script, you should handle it:

<?php
if (isset($_GET['action'])){
  switch($_GET['action']){  
     case 'delete':
       @unlink(listeImages[$_GET['action']].toString());
     break;
     //Other functions you may call
  }
  exit;
}
//The rest of your index.php code
?>