var newWin = null;
var mainWin = null;

function goOttoAD() {
var w = 500;
var h = 405;
var width = screen.availWidth;
var height = screen.availHeight;

if (newWin != null) {
if (!newWin.closed && newWin.close) {
newWin.close();
}
}
 
newWin = window.open('OttoAD.html','OttoAD','width=' + w + ',height=' + h +
',left=' + ((width - w) / 2) + ',top=' + ((height - h) / 2) +
',scrollbars=0,resizeable=0,toolbar=0,menubar=no,statusbar=0');
}