var bodyobj   = document.getElementsByTagName ? document.getElementsByTagName("body")[0] : document.body;
var bgpath    = "./IMG/";
var extension = ".jpg";
var pattern;

if (pattern == "undefined"){ pattern = null }


function setBackground(pattern)
{
	if (pattern == null)
	{
		bodyobj.style.backgroundImage = "";
		bodyobj.style.backgroundColor = "#FFFFFF";
	}
	else
	{
		bodyobj.style.backgroundImage = "url("+ bgpath + pattern + extension +")";
	}
}
document.onload = setBackground(pattern);