jquery 获得浏览器的类型
function GetBrowserType() {
var ua = navigator.userAgent.toLowerCase();
if (ua == null) return "ie";
else if (ua.indexOf('chrome') != -1) return "chrome";
else if (ua.indexOf('opera') != -1) return "opera";
else if (ua.indexOf('msie') != -1) return "ie";
else if (ua.indexOf('safari') != -1) return "safari";
else if (ua.indexOf('firefox') != -1) return "firefox";
else if (ua.indexOf('gecko') != -1) return "gecko";
else return "ie";
}