var Sys = {};
var ua = navigator.userAgent.toLowerCase();
if (window.ActiveXObject)
    Sys.ie = ua.match(/msie ([\d.]+)/)[1]
else if (document.getBoxObjectFor)
    Sys.firefox = ua.match(/firefox\/([\d.]+)/)[1]
else if (window.MessageEvent && !document.getBoxObjectFor)
    Sys.chrome = ua.match(/chrome\/([\d.]+)/)[1]
else if (window.opera)
    Sys.opera = ua.match(/opera.([\d.]+)/)[1]
else if (window.openDatabase)
    Sys.safari = ua.match(/version\/([\d.]+)/)[1];
