function SimpleSwap(el,which) { 
    el.src = el.getAttribute(which || "origsrc"); 
} 
function SimpleSwapSetup(){ 
    var x = document.getElementsByTagName("img"); 
    for (var i=0;i<x.length;i++){ 
    var oversrc = x[i].getAttribute("oversrc"); 
    if (!oversrc) continue; 
    
    // preload image 
    // comment the next two lines to disable image pre-loading 
    x[i].oversrc_img = new Image(); 
    x[i].oversrc_img.src=oversrc; 
    // set event handlers 
    x[i].onmouseover = new Function("SimpleSwap(this,'oversrc');"); 
    x[i].onmouseout = new Function("SimpleSwap(this);"); 
    // save original src 
    x[i].setAttribute("origsrc",x[i].src); 
} 
} 
var PreSimpleSwapOnload =(window.onload)? window.onload : function(){}; 
window.onload = function(){PreSimpleSwapOnload(); SimpleSwapSetup();}