var W3CDOM = (document.createElement && document.getElementsByTagName);

var mouseOvers = new Array();
var mouseOuts = new Array();

window.onload = init;

function init()
{
if (!W3CDOM) return;
var nav = document.getElementById('mouseovers');
var imgs = nav.getElementsByTagName('img');
for (var i=0;i<imgs.length;i++)
{
imgs[i].onmouseover = mouseGoesOver;
imgs[i].onmouseout = mouseGoesOut;
var suffix = imgs[i].src.substring(imgs[i].src.lastIndexOf('.'));
mouseOuts[i] = new Image();
mouseOuts[i].src = imgs[i].src;
mouseOvers[i] = new Image();
mouseOvers[i].src = imgs[i].src.substring(0,imgs[i].src.lastIndexOf('.')) + "_omo" + suffix;
imgs[i].number = i;
}
}

function mouseGoesOver()
{
this.src = mouseOvers[this.number].src;
}

function mouseGoesOut()
{
this.src = mouseOuts[this.number].src;
}