function open_win(goto_url, width, height, scroll) {
	
	var theTop	= (screen.height/2)-(height/2);
	var theLeft = (screen.width/2)-(width/2);
   
	variables="width="+width+", height="+height+", status=no, toolbar=no, menubar=no, scrollbars="+scroll+", top="+theTop+", left="+theLeft+"";
	window.open(""+goto_url+"", "", variables);
}