javascript实现Ajax代码

function AjaxObject() {this.req = null;this.getRequest = function() {if (window.ActiveXObject) {this.req = new ActiveXObject("Microsoft.xmlhttp");} else if (window.XMLHttpRequest) {this.req = new XMLHttpRequest();}}this.sendRequest = function(url, params, Method) {if (!Method) {Method = "POST";}this.getRequest();this.req.onreadystatechange = this.showData;this.req.open(Method, url, true);this.req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");this.req.send(params);}this.showData = function() {}}