function openPopup(url, w, h, st){
	var winl = (screen.width-w)/2; 
	var wint = (screen.height-h)/2; 
	if (winl < 0) 
		winl = 0; 
	if (wint < 0) 
		wint = 0; 
     var settings = "width=" + w +",height=" + h + ", top="+ wint +", left="+winl+",location=no, resizable=no";
     var win = window.open(url,"windowpopup",settings,st);
	 	 win.window.focus(); 

}