var bEnabled = true;
var init = setInterval("slidebackground()",20);
var x = 20;
var y = 20;
var size = 16;

function slidebackground()	{
	if(bEnabled)	{
		if(x > 4)	{
			x--;
			y--;
		}
		else	{
			x = 20;
			y = 20;
		}
		document.getElementById("body").style.backgroundPosition = x +"px "+ y +"px";
	}
}

function toggleBackground()	{
	bEnabled = !bEnabled;
}