您可以检测到所有Internet Explorer(最近测试的版本12)。

<script>
    var $userAgent = '';
    if(/MSIE/i['test'](navigator['userAgent'])==true||/rv/i['test'](navigator['userAgent'])==true||/Edge/i['test'](navigator['userAgent'])==true){
       $userAgent='ie';
    } else {
       $userAgent='other';
    }

    alert($userAgent);
</script>

请看这里https://jsfiddle.net/v7npeLwe/

几年后，Edge浏览器现在使用Chromium作为渲染引擎。 遗憾的是，检查IE 11仍然是一件事。

这里有一个更直接的方法，因为古老版本的IE应该消失了。

if (window.document.documentMode) {
  // Do IE stuff
}

---

以下是我以前的答案(2014年):

在Edge中，用户代理字符串已更改。

/**
 * detect IEEdge
 * returns version of IE/Edge or false, if browser is not a Microsoft browser
 */
function detectIEEdge() {
    var ua = window.navigator.userAgent;

    var msie = ua.indexOf('MSIE ');
    if (msie > 0) {
        // IE 10 or older => return version number
        return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
    }

    var trident = ua.indexOf('Trident/');
    if (trident > 0) {
        // IE 11 => return version number
        var rv = ua.indexOf('rv:');
        return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
    }

    var edge = ua.indexOf('Edge/');
    if (edge > 0) {
       // Edge => return version number
       return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
    }

    // other browser
    return false;
}

示例用法:

alert('IEEdge ' + detectIEEdge());

ie10默认字符串:

Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)

IE 11默认字符串:

Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko 

Edge 12的默认字符串:

Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36 Edge/12.0 

Edge 13的默认字符串(thx @DrCord):

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586 

Edge 14的默认字符串:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/14.14300 

Edge 15的默认字符串:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/15.15063 

Edge 16的默认字符串:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299 

Edge 17的默认字符串:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/17.17134 

Edge 18的默认字符串(内部预览):

Mozilla/5.0 (Windows NT 10.0; Win64; x64; ServiceUI 14) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/18.17730 

在CodePen进行测试:

http://codepen.io/gapcode/pen/vEJNZN

下面我找到了一种优雅的方法，在谷歌上搜索——

/ detect IE
var IEversion = detectIE();

if (IEversion !== false) {
  document.getElementById('result').innerHTML = 'IE ' + IEversion;
} else {
  document.getElementById('result').innerHTML = 'NOT IE';
}

// add details to debug result
document.getElementById('details').innerHTML = window.navigator.userAgent;

/**
 * detect IE
 * returns version of IE or false, if browser is not Internet Explorer
 */
function detectIE() {
  var ua = window.navigator.userAgent;

  // Test values; Uncomment to check result …

  // IE 10
  // ua = 'Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)';

  // IE 11
  // ua = 'Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko';

  // IE 12 / Spartan
  // ua = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36 Edge/12.0';

  // Edge (IE 12+)
  // ua = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586';

  var msie = ua.indexOf('MSIE ');
  if (msie > 0) {
    // IE 10 or older => return version number
    return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
  }

  var trident = ua.indexOf('Trident/');
  if (trident > 0) {
    // IE 11 => return version number
    var rv = ua.indexOf('rv:');
    return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
  }

  var edge = ua.indexOf('Edge/');
  if (edge > 0) {
    // Edge (IE 12+) => return version number
    return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
  }

  // other browser
  return false;
}

我在2020年登陆这个页面，我看到直到IE5所有的userAgent字符串都有Trident，我不确定他们是否有任何改变。所以只检查userAgent中的Trident对我来说是有效的。

var isIE = navigator.userAgent.indexOf('Trident') > -1;

我知道这是一个老问题，但如果有人再次遇到这个问题，并且无法检测IE11，这里有一个适用于所有当前版本的IE的有效解决方案。

var isIE = false;
if (navigator.userAgent.indexOf('MSIE') !== -1 || navigator.appVersion.indexOf('Trident/') > 0) {
    isIE = true;   
}

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!");
}