/**
 * by Tobie: http://dev.rubyonrails.org/attachment/ticket/9760/sniff.diff
 */
Prototype.Browser = (function(agent) {
  function getVersion(identifier) {
    var version = new RegExp(identifier + '([\\d.]+)').exec(agent); 
    return version ? parseFloat(version[1]) : true; 
  } 
  return { 
    IE:     !!(window.attachEvent && !window.opera) && getVersion('MSIE '), 
    Opera:  !!window.opera && getVersion('Opera/'), 
    WebKit: agent.indexOf('AppleWebKit/') > -1 && getVersion('AppleWebKit/'), 
    Gecko:  agent.indexOf('Gecko') > -1 && agent.indexOf('KHTML') == -1 
            && getVersion('Gecko/'), 
    MobileSafari: !!agent.match(/iPhone.*Mobile.*Safari/) 
  }; 
})(navigator.userAgent);