这是在一个html页面中的javascript:<script language="javascript" type="text/javascript">var xmlHttp = false;try { xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");} catch (e) { try { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e2) { xmlHttp = false; }}if (!xmlHttp && typeof XMLHttpRequest != 'undefined') { xmlHttp = new XMLHttpRequest();}function callServer() { var date=new Date(); temp=date.getTime(); //if ((u_name == null) || (u_name == "")) return false; //var url="check.php?timestamp="+temp+"&id="+u_name; var u_name = document.getElementById("userid").value; xmlHttp.open("GET","check.php?timestamp="+temp+"&id="+u_name, true); xmlHttp.onreadystatechange = updatePage; xmlHttp.send(null); }function updatePage() { if (xmlHttp.readyState < 4) {user_id.innerHTML="loading..."; }if (xmlHttp.readyState == 4) {if(xmlHttp.status==200){result=xmlHttp.responseText; c=document.getElementById("user_id");c.innerHTML=result; }else{alert("执行过程中出现问题,服务器返回"+xmlHttp.statusText);} }}</script>php如下:<?phpheader("Content-Type:text/html; charset=UTF-8");$id=$_GET["id"];mysql_connect("localhost","root","123456");mysql_select_db("infornet");mysql_query("SET NAMES GB2312");$sql="SELECT COUNT(*) FROM user WHERE uno='$id'";$result=mysql_query($sql);$num=mysql_fetch_row($result);if($num[0]==0) echo "1";else echo "0";?>每次执行都是红色的那句话,谢谢大家帮个忙啊~~~