JavaScript 如何检查用户是否在使用Internet Explorer

在某些情况下，我们可能需要检查正在使用的浏览器。您的网站的某些功能可能在旧浏览器如Internet Explorer(IE)中不受支持。有不同的方法可以检查正在使用的Internet Explorer版本。

语法-1: 对于Internet Explorer 10或更早的版本

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);
    }

语法-2: 适用于Internet Explorer 11

var ua = window.navigator.userAgent;
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);
    }

语法-3： 针对Internet Explorer 12+（Edge）

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

示例：

<!DOCTYPE html> 
<html> 
  
<head> 
    <title> 
      Detects user uses Internet Explorer 
  </title> 
</head> 
  
<body> 
    <center> 
        <h1 style="color:green">GeeksforGeeks</h1> 
        <script> 
            //detects if user uses Internet Explorer 
            //returns version of IE or false, if browser is not IE 
            //Function to detect IE or not 
            function IEdetection() { 
                var ua = window.navigator.userAgent; 
                var msie = ua.indexOf('MSIE '); 
                if (msie > 0) { 
                    // IE 10 or older, return version number 
                    return ('IE ' + 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 ('IE ' + parseInt(ua.substring( 
                      rv + 3, ua.indexOf('.', rv)), 10)); 
                } 
                var edge = ua.indexOf('Edge/'); 
                if (edge > 0) { 
                    //Edge (IE 12+), return version number 
                    return ('IE ' + parseInt(ua.substring( 
                      edge + 5, ua.indexOf('.', edge)), 10)); 
                } 
                // User uses other browser 
                return ('Not IE'); 
            } 
            var result = IEdetection(); 
            document.write(result); 
        </script> 
    </center> 
</body> 
  
</html>

输出： （使用Firefox打开）：