php中结合Ajax的有关问题

php中结合Ajax的问题
删除页：del.php

HTML code

<!--

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-->
 
  <title>Information</title>
  <script type="text/javascript">
    var xmlHttp ;
    function createXMLHttpRequest(){
        if(window.ActiveXObject){
            xmlHttp=new ActiveXObject("Microsoft.XMLHTTP") ;
        }else if(window.XMLHttpRequest){
            xmlHttp=new XMLHttpRequest() ;
        }
    }

    function show(){
        createXMLHttpRequest() ;
        var url="delsend.php" ;
        xmlHttp.onreadystatechange=callback ;
        xmlHttp.open("GET" , url , true) ;
        xmlHttp.send(null) ;
    }
    function callback(){
        if(xmlHttp.readyState==4){
            if(xmlHttp.status==200){
                chk() ;
            }
        }
    }
    function chk(){
        var xmlDoc=xmlHttp.responseXML ;
        var yan=xmlDoc.getElementsByTagName("content") ;
        var ta="<table border='1' align='center'><th>用户编号<th>用户<th>聊天内容<th>聊天时间<th>操作" ;

        for(var i=0 ; i<yan.length ; i++){
            var y=yan[i] ;
            ta+="<tr><td>"+y.childNodes[0].firstChild.data+"" ;
            ta+="<td>"+y.childNodes[1].firstChild.data+"" ;
            ta+="<td>"+y.childNodes[2].firstChild.data+"" ;
            ta+="<td>"+y.childNodes[3].firstChild.data+"" ;
            ta+="<td><span id="+y.childNodes[4].firstChild.data+" onclick='start(this)'>删除" ;
        }
        ta +="" ;
        document.getElementById("del").innerHTML=ta ;
        //alert(yan.length) ;
    }

    function start(ele){
        var id=ele.id ;
        createXMLHttpRequest() ;
        var urldel="startsend.php?key="+escape(id) ;
        xmlHttp.onreadystatechange=back ;
        xmlHttp.open("GET" , urldel , true) ;
        xmlHttp.send(null) ;
    }
    function back(){
        if(xmlHttp.readyState==4){
                if(xmlHttp.status==200){
                    var str=xmlHttp.responseText ;
                    if(str=="1"){
                    alert("该项已被删除，1秒之后显示新的信息") ;
                    setTimeout("show()" , 1000) ;
                    }
                }
        }
    }
  </script>
 
 
 <?php error_reporting(E_ALL & ~E_NOTICE);
 ?>
  <div align="center">
    <h2>删除信息</h2>
    <div id="del"></div>
  </div>
 

[/code]delsend.php

PHP code

<!--

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--><?php header("Content-Type:text/xml") ;
header("cache-control:no-cache , must-revalidate") ;
error_reporting(E_ALL & ~E_NOTICE);
$xml="<?xml version='1.0' encoding='gb2312'?>" ;
$xml=$xml."<contents>" ;
include_once("conn.php") ;
$result=mysql_query("select * from chatcontent") ;
while($rs=mysql_fetch_object($result)){
    $content.="<content><userid>".$rs->user_id."</userid><name>".$rs->name."</name><content1>".$rs->content."</content1><date>".$rs->showdate."</date><time>".$rs->id."</time></content>" ;
}
$xml=$xml.$content."</contents>" ;
echo $xml ;

mysql_close() ;
?>

[/code]startsend.php

PHP code

<!--

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--><?php error_reporting(E_ALL & ~E_NOTICE);
    $id=$_GET["key"] ;
    include_once("conn.php") ;
    $result=mysql_query("delete from chatcontent where id='$id'") ;
    if($result){
        echo "1" ;
        //echo "<script type='text/javascript'>window.location='del.php' ;" ;
    }
    mysql_close() ;
?>

 <div class="clear">
                 
              
              
        
            </div>