var Browser = 
{
	IE: !!document.all,
	IE6: document.all && !window.XMLHttpRequest,
	IE7: document.all && window.XMLHttpRequest && !document.querySelectorAll,
	IE8: document.all && window.XMLHttpRequest && document.querySelectorAll,
	IE7plus: document.all && window.XMLHttpRequest,
	Opera: !!window.opera,
    Chrome: window.MessageEvent && !document.getBoxObjectFor,
	Safari: !!window.openDatabase,
    WebKit: navigator.userAgent.indexOf('AppleWebKit/') > -1,
	FireFox: !!document.getBoxObjectFor,
	FireFox2: document.getBoxObjectFor && !document.documentElement.getBoundingClientRect,
	FireFox3: document.getBoxObjectFor && document.documentElement.getBoundingClientRect,
	FireFox3dot1: navigator.userAgent.indexOf('Shiretoko') >-1,
    Gecko:  navigator.userAgent.indexOf('Gecko') > -1 && navigator.userAgent.indexOf('KHTML') == -1,//不可靠
    MobileSafari: !!navigator.userAgent.match(/Apple.*Mobile.*Safari/)
}