function userBrowser(){

    var browserName=navigator.userAgent.toLowerCase();

    if(/msie/i.test(browserName) && !/opera/.test(browserName)){

        alert("IE");

        return ;

    }else if(/firefox/i.test(browserName)){

        alert("Firefox");

        return ;

    }else if(/chrome/i.test(browserName) && /webkit/i.test(browserName) && /mozilla/i.test(browserName)){

        alert("Chrome");

        return ;

    }else if(/opera/i.test(browserName)){

        alert("Opera");

        return ;

    }else if(/webkit/i.test(browserName) &&!(/chrome/i.test(browserName) && /webkit/i.test(browserName) && /mozilla/i.test(browserName))){

        alert("Safari");

        return ;

    }else{

        alert("unKnow");

    }

}