function OpenChatWindow()
{
 var nHoogte = screen.availHeight - 150;
 var nBreedte = 340;
 var cProperties = "top=0, left=" + eval(screen.availWidth - nBreedte - 10);
 cProperties += ", height=" + eval(nHoogte);
 cProperties += ", width=" + nBreedte;
 cProperties += ", scrollbars=yes, resizable=yes";

 window.open("chat.asp", "Chat", cProperties);
 return true;
}