// returns whether the browser is supported
    function isBrowserSupported() {
        if (/Firefox[\/\s](\d+\.\d+)/.test(navigator.userAgent)){
            var ffVersion=new Number(RegExp.$1); 
            if (ffVersion>=2) {
                return true;   
            }
        } else if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)){ 
            var ieVersion=new Number(RegExp.$1)
            if (ieVersion >= 6) {
                return true;
            }
        } else if (/Safari/.test(navigator.userAgent)) {
            if (/AppleWebKit\/(\d+\.\d+)/.test(navigator.userAgent)) {
                var appleWebKitVersion = new Number(RegExp.$1); 
                if (appleWebKitVersion >= 312) {
                    return true;
                }
            }
        }
        return false;
    }
    // Returns whether browser is IE6 or lower
    function isIE6OrLower() {
        if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)) {
            var ieVersion = new Number(RegExp.$1)
            if (ieVersion <= 6) {
                return true;
            }
        }
        return false;
    }