function OpenWindowCenter(mypage, myname, w, h, s) {
    s = typeof(s) == "undefined" ? 'no' : s; 
	var winl = (screen.width - w) / 2;
    var wint = (screen.height - h) / 2;
    winprops = 'scrollbars='+s+',toolbar=no,location=no,status=no,menubar=no,height='+h+',width='+w+',top='+wint+',left='+winl
    win = window.open(mypage, myname, winprops)
    if (parseInt(navigator.appVersion) >= 4) {
       win.window.focus();
    }
}