方法一：

 // 判斷瀏覽器函式
    function isMobile(){
        if(window.navigator.userAgent.match(/(phone|pad|pod|iPhone|iPod|ios|iPad|Android|Mobile|BlackBerry|IEMobile|MQQBrowser|JUC|Fennec|wOSBrowser|BrowserNG|WebOS|Symbian|Windows Phone)/i)) {
            return true;  // 移動端
        }else{
            return false;  // PC端
        }
    }
 

方法二：這個方法摘自：im.qq.com

var os = function() {  
     var ua = navigator.userAgent,  
     isWindowsPhone = /(?:Windows Phone)/.test(ua),  
     isSymbian = /(?:SymbianOS)/.test(ua) || isWindowsPhone,   
     isAndroid = /(?:Android)/.test(ua),   
     isFireFox = /(?:Firefox)/.test(ua),   
     isChrome = /(?:Chrome|CriOS)/.test(ua),  
     isTablet = /(?:iPad|PlayBook)/.test(ua) || (isAndroid && !/(?:Mobile)/.test(ua)) || (isFireFox && /(?:Tablet)/.test(ua)),  
     isPhone = /(?:iPhone)/.test(ua) && !isTablet,  
     isPc = !isPhone && !isAndroid && !isSymbian;  
     return {  
          isTablet: isTablet,  
          isPhone: isPhone,  
          isAndroid : isAndroid,  
          isPc : isPc  
     };  
}();  

// 使用方法 
if(os.isAndroid || os.isPhone){
alert("-----");
}
 

判斷是否為微信客戶端：

 var isWechart = function () {
        var rst = true
        if(window.navigator.userAgent.match(/(phone|pad|pod|iPhone|iPod|ios|iPad|Android|Mobile|BlackBerry|IEMobile|MQQBrowser|JUC|Fennec|wOSBrowser|BrowserNG|WebOS|Symbian|Windows Phone)/i)){
            var ua = navigator.userAgent.toLowerCase();
            if (!(ua.match(/MicroMessenger/i) == "micromessenger")) {
                rst = false;
            }
        }else {
            rst = false;
        }
        return rst;
    }