Ajax and PHP

js代码：

		var xmlHttp=createXmlHttpRequestObject();
		//get xmlHttpRequest object
		function createXmlHttpRequestObject(){
			var xmlHttp;
			if(window.ActiveXObject){
				try{
					xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
					}
					catch(e){
						xmlHttp=false;
						}
				}else{
					try{
						xmlHttp=new XMLHttpRequest();
						
						}
						catch(e){
							xmlHttp=false;
							}
							
					}
				if(!xmlHttp){
								}else{
									return xmlHttp;
									}
					}
					
		function process(){
			if(xmlHttp.readyState==4||xmlHttp.readyState==0){
				name=document.getElementById("myName").value;
				
				xmlHttp.open("GET","quickstart.php?name="+name,true);
				xmlHttp.
				xmlHttp.send(null);
					
				
				}else{
					setTimeout('process()',1000);
					}
		}
		
		function handleServerResponse(){
			if(xmlHttp.readyState==4){
				if(xmlHttp.status==200){
					xmlResp
					xmlDocumentElement=xmlResponse.documentElement;
					helloMessage=xmlDocumentElement.firstChild.data;
					document.getElementById('divMessage').innerHTML='<i>'+helloMessage+'</i>';
					setTimeout('process()',1000);
				
					}else{
						alert('There was a problem accessing hte server:'+xmlHttp.statusText);
						}
				}
			}

php代码：

遇到了 一个

<pre name="code" class="plain">Warning: Cannot modify header information - headers already sent by....

解决方法：

修改php.ini文件，

我用的是阿里的服务器所以

启用如下如的功能就可以了。

<img src="http://img.blog.csdn.net/20160319103516024?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

<pre name="code" class="php"><?php
header(&#39;Content-Type:text/xml&#39;);
echo &#39;<?xml version="1.0" encoding="UTF-8" standal
echo&#39;<response>';
$name=$_GET['name'];
$userNames=array('WangWei','ZhouJianfei','MeiShibo','QuXinglin','WangYuming','LiaoGuihong','WangChenggao','ZhouQian');
if(in_array($name,$userNames)){
echo'Hello,master'.htmlentities($name).'!';
}else if(trim($name)==''){
echo'Stranger,please tell me your name!';
}else{
echo htmlentities($name).',I don\'t know you!';
}
echo'</response>';
?>

<pre name="code" class="php">方法简介：

in_array($name,$userNames)：遍历uername数组中的元素，并每次赋值给name

strtoupper($str);将该str转换为大写。

<pre name="code" class="php">htmlentities($name):替换代码中不同字符的编码（eg：&，>等）,以防止出错。