var http_request=false;
  function send_request(url){//初始化，指定处理函数，发送请求的函数
    http_request=false;
	//开始初始化XMLHttpRequest对象
	if(window.XMLHttpRequest){//Mozilla浏览器
	 http_request=new XMLHttpRequest();
	 if(http_request.overrideMimeType){//设置MIME类别
	   http_request.overrideMimeType("text/xml");
	 }
	}
	else if(window.ActiveXObject){//IE浏览器
	 try{
	  http_request=new ActiveXObject("Msxml2.XMLHttp");
	 }catch(e){
	  try{
	  http_request=new ActiveXobject("Microsoft.XMLHttp");
	  }catch(e){}
	 }
    }
	if(!http_request){//异常，创建对象实例失败
	 window.alert("创建XMLHttp对象失败！");
	 return false;
	}
	http_request.onreadystatechange=processrequest;
	//确定发送请求方式，URL，及是否同步执行下段代码
    http_request.open("GET",url,true);
	http_request.send(null);
  }
  //处理返回信息的函数
  function processrequest(){
   if(http_request.readyState==4){//判断对象状态
     if(http_request.status==200){//信息已成功返回，开始处理信息
	  document.getElementById(reobj).innerHTML=http_request.responseText;
	 }
	 else{//页面不正常
	  alert("您所请求的页面不正常！");
	 }
   }
  }
  function usercheck(obj){
   var f=document.hyregform;
   var username=f.username.value;
   if(username==""){
   document.getElementById(obj).innerHTML="&nbsp;<font color=red>用户名不能为空！</font>";
	//f.username.focus();
	return false;
   }
   else{
   document.getElementById(obj).innerHTML="正在读取数据...";
   send_request('mem_check.php?username='+username);
   reobj=obj;
   }
  }

  function checkform(obj){
    var f=document.reg;
	var username=f.username.value;

	if(username==""){
	  document.getElementById(obj).parentNode.style.display="";
	  document.getElementById(obj).innerHTML="&nbsp;<font color=red>您还未填写完整，带*为必填内容！</font>";
          return false;
	}
	else {
	  document.getElementById(obj).parentNode.style.display="";
	  document.getElementById(obj).innerHTML="正在发送数据...";
          send_request('mem_check.php?username='+username);
          reobj=obj;
	}
  }