判断浏览器及版本

//"webkit":safari或chrome
//"opera":Opera
//"mozilla":Firefox或者其他gecko内核的浏览其
//"msie":IE 

var browser=(function(){
  var s=navigator.userAgent.toLowerCase();
  var match=/(webkit)[\/]([\w.]+)/.exec(s)||
      /(opera)(?:.*version)?[ \/]([\w.]+)/.exec(s)||
      /(msie)([\w.]+)/.exec(s)||
      !/compatible/.test(s)&&/(mozilla)(?:.*? rv:([\w.]+))?/.exec(s)||[];
  return {name:match[1]||"",version:match[2]||"0"};
}());

//document.getElementById("test").innerHTML=JSON.stringify(browser);