最近使用Ajax技术通过XMLHttpRequest对象完成一个首页的登录功能！

代码如下：

<script type="text/javascript">//创建XMLHttpRequest对象function createXMLHttpRequest(){if(window.XMLHttpRequest){return xmlhttprequest=new XMLHttpRequest();}else{return xmlhttprequest=new ActiveXObject("Microsoft.XMLHTTP");}}//登录按钮执行的方法function doStart(){var logname=document.getElementById("loginName").value;var logpass=document.getElementById("loginPsw").value;var userinfo="inAccount="+logname+"&inPsw="+logpass;var url="users/users_pswCheck.action";xmlhttprequest=createXMLHttpRequest();xmlhttprequest.onreadystatechange=getresultValue;xmlhttprequest.open("post",url,true);xmlhttprequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded");xmlhttprequest.send(userinfo);}//回调方法function getresultValue(){if(xmlhttprequest.readyState==4 && xmlhttprequest.status==200){var result=xmlhttprequest.responseText;if(result=="success"){window.location.href="index.jsp" rel="external nofollow" ;} else {document.getElementById("xiaoxi").innerHTML="登录失败！";}}}//页面的按键事件，即当按的是回车键时触发该事件function keybutton(){if(event.keyCode==13){ doStart(); return;} }</script>