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
        {
         	//try{var tmp = xmlhttp.responseXML.xml}catch(ex){err=true;} 
         	var res="";
         	try
         	{
         		res=http_request.responseText;
         	}
         	catch(ex){
         		alert("系统出错");
         	}
         	if (res=="error:1")
         	{
            	alert("该序列号不存在");
            } 
            else if (res=="error:2")
            {
            	alert("该序列号已注册")
;;
            }
            else 
            {
             	//alert(res);
             	document.getElementById("type").innerText=res;
             }
        }
        else  //页面不正常
        {
            alert("您所请求的页面不正常！");
        }
    }
} 

function checkSerial()
 
{ 	
	var f= document.form1;
	var serial=f.serial.value;
	if (serial=="")
	{
		alert("请输入序列号")
;
		return false;
	} 
	else
	{
		send_request('checksn.php?serial='+serial);
	}
	return false;
} 

function checkfourm(obj)
{
    var f=document.fourm;
    var newfourm=f.newfourm.value;
    var username=f.username.value;
    var id=f.id.value;
    if(username=="")
    {
        document.getElementById(obj).innerHTML="<img src=images/false.gif> <font color=red>您必须先登录！</font>";
        return false;
    }
    else if(newfourm=="")
    {
        document.getElementById(obj).innerHTML="<img src=images/false.gif> <font color=red>您还没填写评论内容！</font>";
        return false;
    }
    else
    {
        document.getElementById(obj).innerHTML="正在发送数据";
        send_request('sendnewfourm.php?username='+username+'&newfourm='+newfourm+'&id='+id);
        reobj=obj;
    }
}