本人ajax留言板的源程序 不错的应用js

        if(!xmlhttp)
        {
            alert("你的浏览器不支持XMLHTTP！！");
            return;
        }
        xmlhttp.onreadystatechange=requestdata;
        xmlhttp.open("GET",url,true);
        xmlhttp.send(null);
        function requestdata()
        {

                fopen(obj1);
                echo(obj1,"正在加载数据，请稍等......");
                if(xmlhttp.readyState==4)
                {
                    if(xmlhttp.status==200)
                    {
                        if(obj1!=obj2){fclose(obj1);};
                        echo(obj2,xmlhttp.responseText);

                    }
                }

        }
}
function postdata(url,obj,data)
{
        var xmlhttp=createxmlhttp();
        if(!xmlhttp)
        {
            alert("你的浏览器不支持XMLHTTP！！");
            return;
        }
        xmlhttp.open("POST", url, true);
        xmlhttp.onreadystatechange=requestdata;
        xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
        xmlhttp.send(data);