跪求ajax有关问题-php教程-PHP中文網

跪求ajax有关问题

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發布： 2016-06-13 12:11:25

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跪求ajax问题

<br /><!DOCUTYPE html><br /><html><br />	<head><br />		<title>聊天窗口</title><br />		<meta http-equiv="Content-type" content="text/html; charset=UTF-8"><br />	</head><br />	<script type="text/javascript"><br />	 window.resizeTo(580,650);<br />	 window.setInterval("getMessage()", 3000);<br />	 <br />	 function getXmlHttpObject(){<br />		var xmlHttpRequest;<br />		//不同的浏览器获取对象xmlhttprequest对象方法不一样<br />		if(window.ActiveXObject){<br />			xmlHttpRequest =new ActiveXObject("Microsoft.XMLHTTP");<br />		}else{<br />			xmlHttpRequest =new XMLHttpRequest();<br />		}<br />		return xmlHttpRequest;<br />	}<br /><br />	function getMessage()<br />	{<br />		var myXmlHttpRequest = getXmlHttpObject();<br /><br />	 	if(myXmlHttpRequest)<br />	 	{<br />	 		var url = "getMessage.php";<br />	 		var data = "getter=<?php @session_start(); echo $_SESSION['username'];?>&sender=<?php echo $_GET['username'];?>";<br /><br />	 		myXmlHttpRequest.open("post",url,true);<br />	 		myXmlHttpRequest.setRequestHeader("Content-type","application/x-www-form-urlencoded");<br /><br />	 		myXmlHttpRequest.onreadystatechange=function()<br />	 		{<br />		 		if(myXmlHttpRequest.readyState==4)<br />		 		{<br />		 			if(myXmlHttpRequest.status==200)<br />		 			{<br />		 				//接收<br />		 				var mes=myXmlHttpRequest.responseXML;<br />		 				<br />		 				window.alert(mes);  //这里打印出来老是为null<br />		 			}<br />		 		}<br />	 		}<br />	 		myXmlHttpRequest.send(data);<br />	 	}<br /><br />	}<br /><br />	 function sendMessage()<br />	 {<br />	 	var myXmlHttpRequest = getXmlHttpObject();<br /><br />	 	if(myXmlHttpRequest)<br />	 	{<br />	 		var url = "sendMessage.php";<br />	 		var data = "con=" + $('con').value +"&getter=<?php echo $_GET['username'];?>"+"&sender=<?php @session_start(); echo $_SESSION['username'];?>";<br /><br />		 	myXmlHttpRequest.open("post",url,true);<br />		 	myXmlHttpRequest.setRequestHeader("Content-type","application/x-www-form-urlencoded");<br />		 	myXmlHttpRequest.onreadystatechange=function()<br />		 	{<br />		 		if(myXmlHttpRequest.readyState==4)<br />		 		{<br />		 			if(myXmlHttpRequest.status==200)<br />		 			{<br /><br />		 			}<br />		 		}<br />		 	}<br />		 	myXmlHttpRequest.send(data);<br />	 	}<br />	<br />	 }<br /><br />	 function $(id)<br />	 {<br />		return document.getElementById(id);<br />	 }<br />	</script><br />	<body><br />		<center><br />			<h2><span style="color:red;"><?php @session_start(); echo $_SESSION['username'];?></span>跟<span style="color:red;"><?php echo $_GET['username'];?></span>聊天</h2><br />			<textarea name="context" rows="20" cols="70"></textarea><br/><br />			<input style="width:300px" type="text" name="sendcontext" id="con"><br />			<input type="button" name="send" onclick="sendMessage();" value="发送"><br />		</center><br />	</body><br /><br /></html><br />

登入後複製

上面的getMessage()函数是获取ajax查找出来的数据,getMessage()函数里面的.onreadystatechange指定的回调函数中window.alert(mes);打印出来老是为空，但是我ajax请求的getMessage页面有返回数据啊，下面是ajax请求getMessage的代码

<br /><?php<br />	include "MessageServer.class.php";<br />	@header( 'Content-Type:text/xml;charset=utf-8'); <br />	@header("Cache-Control: no-cache");<br />	$getter = $_POST['getter'];<br />	$sender = $_POST['sender'];<br /><br />	//调用MessageSerive获取信息<br />	$messageServer = new MessageServer();<br /><br />	$messList = $messageServer->getMessage($getter, $sender);<br /><br />	echo $messList;<br />	<br />?><br />

登入後複製

echo $messLis t是有数据输出的,输出的是
------解决思路----------------------
                 //接收
                 var mes=myXmlHttpRequest.responseXML;
if(mes.xml == '') {
alert(myXmlHttpRequest.responseText);
return;
}
               window.alert(mes);  //这里打印出来老是为null

------解决思路----------------------
是数据流，你没有定义输入的内容格式，可以是json或数据
------解决思路----------------------
if(myXmlHttpRequest.status==200) {
if(myXmlHttpRequest.recvType=="XML")
     echo  myXmlHttpRequest.responseXML;
}