Js检测浏览器及版本.

      var userAgent = navigator.userAgent,  
      rMsie = /(msie\s|trident.*rv:)([\w.]+)/,  
      rFirefox = /(firefox)\/([\w.]+)/,  
      rOpera = /(opera).+version\/([\w.]+)/,  
      rChrome = /(chrome)\/([\w.]+)/,  
      rSafari = /version\/([\w.]+).*(safari)/; 
      var browser; 
      var version; 
      var ua = userAgent.toLowerCase(); 
      function uaMatch(ua) { 
          var match = rMsie.exec(ua); 
          if (match != null) { 
              return { browser : "IE", version : match[2] || "0" }; 
          } 
          var match = rFirefox.exec(ua); 
          if (match != null) { 
              return { browser : match[1] || "", version : match[2] || "0" }; 
          } 
          var match = rOpera.exec(ua); 
          if (match != null) { 
              return { browser : match[1] || "", version : match[2] || "0" }; 
          } 
          var match = rChrome.exec(ua); 
          if (match != null) { 
              return { browser : match[1] || "", version : match[2] || "0" }; 
          } 
          var match = rSafari.exec(ua); 
          if (match != null) { 
              return { browser : match[2] || "", version : match[1] || "0" }; 
          } 
          if (match != null) { 
              return { browser : "", version : "0" }; 
          } 
      } 
      var browserMatch = uaMatch(userAgent.toLowerCase()); 
      if (browserMatch.browser) { 
          browser = browserMatch.browser; 
          version = browserMatch.version; 
      } 

      console.log("浏览器:",browser," 版本:",version);