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;
        x[i].oversrc_img = new Image();
        x[i].oversrc_img.src=oversrc;
        x[i].onmouseover = new Function("SimpleSwap(this,'oversrc');");
        x[i].onmouseout = new Function("SimpleSwap(this);");
        x[i].setAttribute("origsrc",x[i].src);
    }
}

var PreSimpleSwapOnload =(window.onload)? window.onload : function(){};
window.onload = function(){
    PreSimpleSwapOnload(); SimpleSwapSetup();
}