var win = null;
var w = null;
var h = null;

if (screen.height >= 864 && screen.width >= 1152) {
w = 900;
h = 700;
}
else {
if (screen.height >= 768 && screen.width >= 1024) {
w = 800;
h = 600;
}
else {
w = 600;
h = 400;
   }
}

function NewWindow(mypage,myname,scroll){
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'
win = window.open(mypage,myname,settings)
}