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];
if(Sys.firefox){
    HTMLElement.prototype.__defineGetter__("children",
         function () {
             var returnValue = new Object();
             var number = 0;
             for (var i=0; i
                 if (this.childNodes[i].nodeType == 1) {
                     returnValue[number] = this.childNodes[i];
                     number++;
                 }
             }
             returnValue.length = number;
             return returnValue;
         }
     );
 }