function preload(urls)
{
var d=document; 
if(d.images){
var i;
d.preloaded = new Array();
for(i=0; i<urls.length; i++)
{
	var img = new Image;
	img.src = urls[i];
	d.preloaded[i] = img;
}
}
}

function cimg(elt, url)
{
var d=document; 
var img=d.getElementById(elt);
if (img && img.src)
   img.src = url;
}