function popup(doc_name,wnd_name) 
{
var winl = (screen.width - 350) / 2;
var wint = (screen.height - 420) / 2;

myWin = window.open (doc_name,wnd_name,"width=350,height=420,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,left="+winl+",top="+wint+"");
myWin.focus();
}