function popup(url,name,windowWidth,windowHeight){
		myleft=(screen.width)?(screen.width-windowWidth)/2:100;
		mytop=(screen.height)?(screen.height-windowHeight)/2:100;
		properties = "width="+windowWidth+",height="+windowHeight+",scrollbars=no, top="+mytop+",left="+myleft;
		window.open(url,name,properties)
		}