jquery判断浏览器型号和版本

        var userAgent = window.navigator.userAgent.toLowerCase();
        var version = $.browser.version;
        $(".info").html(version);
        if ($.browser.msie) {
            alert("this is msie");
        }
        else if ($.browser.safari) {
            alert("this is safari!");
        }
        else if ($.browser.mozilla) {
            alert("this is mozilla!");
        }
        else if ($.browser.opera) {
            alert("this is opera");
        }
        else {
            alert("i don't konw!");
        }
        if (version == "6.0") { alert("6.0"); }