js判断浏览器种类以及版本号（从jquery1.8中抠出来的）

 var myLibs = {
     // Use of jQuery.browser is frowned upon.
     // More details: http://api.jquery.com/jQuery.browser
     // jQuery.uaMatch maintained for back-compat
     browser:(function(){
         var 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 ) ||
                 [];

             return {
                 browser: match[ 1 ] || "",
                 version: match[ 2 ] || "0"
             };
         };

         var matched = 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;
         }
         return browser;
     })()
 };

 console.log(myLibs.browser.mozilla);//true
 console.log(myLibs.browser.version);//39.0