function preloadBtnPix() {
	//preload btn images
	btnl =  new Image(8,15);
	btnl.src = "http://www.uptimedata.com/btn/btnl.jpg";
	btnl_h =  new Image(8,15);
	btnl_h.src = "http://www.uptimedata.com/btn/btnl_h.jpg";
	
	btnc =  new Image(8,15);
	btnc.src = "http://www.uptimedata.com/btn/btnc.jpg";
	btnc_h =  new Image(8,15);
	btnc_h.src = "http://www.uptimedata.com/btn/btnc_h.jpg";
	
	btnr =  new Image(8,15);
	btnr.src = "http://www.uptimedata.com/btn/btnr.jpg";
	btnr_h =  new Image(8,15);
	btnr_h.src = "http://www.uptimedata.com/btn/btnr_h.jpg";
	}