changing script src using javascript

[MindlessXD]

<script type="text/javascript"> 
 function reload() { 
 setTimeout("reload()", 5 * 1000) 
 i += 1; 
 document.getElementById('sb_js').src = 'sbjs.php?x=' + i; 
 alert(document.getElementById('sb_js').src); 
 sbjs_write(); //function in sbjs.php 
 } 
 </script> 
 <script id="sb_js" type="text/javascript" src="" onload="reload();"></script>

sb_js's src changes but the new file seems to not have been loaded
is there any way to swap one script for another?
i'm trying to use different javascripts to replace information on the page w/o refreshing the page (something like AJAX)

I appologize if this is ugly code... I'm not much of a JS programmer.

[MindlessXD]

never mind... answer here: [zingzoom.com...]

[Rambo Tribble]

I think it's a bit simpler just to do something like:

var new_scr=document.createElement('script');
new_scr.src="whatever.js";
document.getElementsByTagName('head')[0].appendChild(new_scr);

That approach seems to work in most recent browsers. Safari may be an exception, as Konqueror is.