prototype.jsのブラウザ判定

prototype.jsのコードに書いてあったのでメモ。

UserAgent判定

  Browser: (function(){
    var ua = navigator.userAgent;
    var isOpera = Object.prototype.toString.call(window.opera) == '[object Opera]';
    return {
      IE:             !!window.attachEvent && !isOpera,
      Opera:          isOpera,
      WebKit:         ua.indexOf('AppleWebKit/') > -1,
      Gecko:          ua.indexOf('Gecko') > -1 && ua.indexOf('KHTML') === -1,
      MobileSafari:   /Apple.*Mobile.*Safari/.test(ua)
    }
  })(),

各ブラウザの機能

  BrowserFeatures: {
    XPath: !!document.evaluate,
    SelectorsAPI: !!document.querySelector,
    ElementExtensions: (function() {
      var constructor = window.Element || window.HTMLElement;
      return !!(constructor && constructor.prototype);
    })(),
    SpecificElementExtensions: (function() {
      if (typeof window.HTMLDivElement !== 'undefined')
        return true;

      var div = document.createElement('div');
      var form = document.createElement('form');
      var isSupported = false;

      if (div['__proto__'] && (div['__proto__'] !== form['__proto__'])) {
        isSupported = true;
      }

      div = form = null;

      return isSupported;
    })()
  },