function createXHR() { if (typeof XMLHttpRequest != 'undefined') { return new XMLHttpRequest(); } else if (typeof ActiveXObject != 'undefined') { var&
//跨浏览器添加事件 function addEvent(obj, type, fn) { if (obj.addEventListener) { obj.addEventListener(type, fn, false); } else if (obj.attachEvent) { obj.attachEvent('on' + t