//var win = null;

function PopWindow(mypage,myname,w,h,scroll){
var win = null;
LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
TopPosition = (screen.height) ? (screen.height-h)/2 : 0;
settings = 'height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+',scrollbars='+scroll+',resizable=no,menubar=no,toolbar=no,location=no,status=no,directories=no';
win = window.open(mypage,myname,settings);
win.window.focus();
//<a href="" onClick="PopWindow(this.href,'name','640','400','yes');return false">
}