function popup(file,tx,ty,name,scrollBar) {
	if(scrollBar == "") scrollBar="no"
	
	var top=(screen.height-ty)/2;
	var left=(screen.width-tx)/2;
	
	myWindow = open(file, name, "width="+tx+",height="+ty+",scrollbars="+scrollBar+",menubar=no,resizable=no,status=no,toolbar=no,top="+top+",left="+left+"");
}