我只是想检查一下浏览器是否是IE11或更老的版本，因为它们都是垃圾。

function isCrappyIE() {
    var ua = window.navigator.userAgent;
    var crappyIE = false;
    var msie = ua.indexOf('MSIE ');
    if (msie > 0) {// IE 10 or older => return version number        
        crappyIE = true;
    }
    var trident = ua.indexOf('Trident/');
    if (trident > 0) {// IE 11 => return version number        
        crappyIE = true;
    }
    return crappyIE;
}   

if(!isCrappyIE()){console.table('not a crappy browser);}

使用上面的答案;简单压缩返回布尔值:

var isIE = /（MSIE|三叉戟\/|Edge\/）/i.test（navigator.userAgent）;

方法1: 美元。浏览器在jQuery 1.3版中已弃用，并在1.9版中被移除

if ( $.browser.msie) {
  alert( "Hello! This is IE." );
}

方法2: 使用条件注释

<!--[if gte IE 8]>
<p>You're using a recent version of Internet Explorer.</p>
<![endif]-->

<!--[if lt IE 7]>
<p>Hm. You should upgrade your copy of Internet Explorer.</p>
<![endif]-->

<![if !IE]>
<p>You're not using Internet Explorer.</p>
<![endif]>

方法03:

 /**
 * Returns the version of Internet Explorer or a -1
 * (indicating the use of another browser).
 */
function getInternetExplorerVersion()
{
    var rv = -1; // Return value assumes failure.

    if (navigator.appName == 'Microsoft Internet Explorer')
    {
        var ua = navigator.userAgent;
        var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
        if (re.exec(ua) != null)
            rv = parseFloat( RegExp.$1 );
    }

    return rv;
}

function checkVersion()
{
    var msg = "You're not using Internet Explorer.";
    var ver = getInternetExplorerVersion();

    if ( ver > -1 )
    {
        if ( ver >= 8.0 ) 
            msg = "You're using a recent copy of Internet Explorer."
        else
            msg = "You should upgrade your copy of Internet Explorer.";
    }

    alert( msg );
}

方法04: 使用JavaScript/手动检测

/*
     Internet Explorer sniffer code to add class to body tag for IE version.
     Can be removed if your using something like Modernizr.
 */
 var ie = (function ()
 {

     var undef,
     v = 3,
         div = document.createElement('div'),
         all = div.getElementsByTagName('i');

     while (
     div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i>< ![endif]-->',
     all[0]);

     //append class to body for use with browser support
     if (v > 4)
     {
         $('body').addClass('ie' + v);
     }

 }());

参考链接

Necromancing。

为了不依赖于user-agent字符串，只需检查以下几个属性:

if (document.documentMode) 
{
    console.log('Hello Microsoft IE User!');
}

if (!document.documentMode && window.msWriteProfilerMark) {
    console.log('Hello Microsoft Edge User!');
}

if (document.documentMode || window.msWriteProfilerMark) 
{
    console.log('Hello Microsoft User!');
}

if (window.msWriteProfilerMark) 
{
    console.log('Hello Microsoft User in fewer characters!');
}

此外，这将检测新的Chredge/Edgium(阿纳海姆):

function isEdg()
{ 

    for (var i = 0, u="Microsoft", l =u.length; i < navigator.plugins.length; i++)
    {
        if (navigator.plugins[i].name != null && navigator.plugins[i].name.substr(0, l) === u)
            return true;
    }

    return false;
}

这个可以检测铬:

function isChromium()
{ 

    for (var i = 0, u="Chromium", l =u.length; i < navigator.plugins.length; i++)
    {
        if (navigator.plugins[i].name != null && navigator.plugins[i].name.substr(0, l) === u)
            return true;
    }

    return false;
}

还有这个Safari:

if(window.safari)
{
    console.log("Safari, yeah!");
}

我用过这个

function notIE(){
    var ua = window.navigator.userAgent;
    if (ua.indexOf('Edge/') > 0 || 
        ua.indexOf('Trident/') > 0 || 
        ua.indexOf('MSIE ') > 0){
       return false;
    }else{
        return true;                
    }
}

如果你使用的是jquery版本>=1.9，试试这个，

var browser;
jQuery.uaMatch = function (ua) {
    ua = ua.toLowerCase();

    var match = /(chrome)[ \/]([\w.]+)/.exec(ua) ||
        /(webkit)[ \/]([\w.]+)/.exec(ua) ||
        /(opera)(?:.*version|)[ \/]([\w.]+)/.exec(ua) ||
        /(msie) ([\w.]+)/.exec(ua) || 
        ua.indexOf("compatible") < 0 && /(mozilla)(?:.*? rv:([\w.]+)|)/.exec(ua) ||
       /(Trident)[\/]([\w.]+)/.exec(ua) || [];

    return {
        browser: match[1] || "",
        version: match[2] || "0"
    };
};
// Don't clobber any existing jQuery.browser in case it's different
if (!jQuery.browser) {
    matched = jQuery.uaMatch(navigator.userAgent);
    browser = {};

    if (matched.browser) {
        browser[matched.browser] = true;
        browser.version = matched.version;
    }

    // Chrome is Webkit, but Webkit is also Safari.
    if (browser.chrome) {
        browser.webkit = true;
    } else if (browser.webkit) {
        browser.safari = true;
    }

    jQuery.browser = browser;
}

如果使用jQuery版本<1.9($。浏览器在jQuery 1.9中被移除)使用以下代码代替:

$('.myClass').on('click', function (event) {
    if ($.browser.msie) {
        alert($.browser.version);
    }
});