Ajax实现评论提交

document.write('<div id="loadingg"  style="height:65px; width: 205px;position: absolute; z-index:1000;border:3px #fff solid;text-align:center; font-size:12px; font-family:arial, helvetica, sans-serif;color:#660000;background:#222;opacity:.7;-moz-opacity:.7;filter: alpha(opacity=70); display:none;"><br/><font color="#ff6600"><strong>数据正在读取中,请等候...</strong></font><br/><img src="images/loading.gif"/></div>')
function showloading() 
{
var obj=document.getelementbyid("loadingg")
if (obj.style.display!="")
{
obj.style.left=((document.documentelement.clientwidth-parsefloat (obj.style.width))/2)+document.documentelement.scrollleft+"px";
obj.style.top=((document.documentelement.clientheight-parsefloat (obj.style.height))/2)+document.documentelement.scrolltop+"px";
obj.style.display="";
}else{obj.style.display="none";}
}
function $(id)
{    return document.getelementbyid(id);    }
function echo(obj,html){    $(obj).innerhtml=html;}
function fopen(obj){$(obj).style.display="";}
function fclose(obj){$(obj).style.display="none";}
function createxmlhttp(){
    var xmlhttp=false;
    try    {
          xmlhttp = new activexobject("msxml2.xmlhttp");
     } 
    catch (e) {
          try {
               xmlhttp = new activexobject("microsoft.xmlhttp");
          } 
        catch (e) {
               xmlhttp = false;
         }
     }
    if (!xmlhttp && typeof xmlhttprequest!='undefined') {
          xmlhttp = new xmlhttprequest();
                if (xmlhttp.overridemimetype) {//设置mime类别
            xmlhttp.overridemimetype('text/xml');
        }
    }    
    return xmlhttp;    
}

function getdata(url,obj1,obj2)
{        var xmlhttp=createxmlhttp();
        if(!xmlhttp)
        {alert("你的浏览器不支持xmlhttp！！");
            return;
        }
        showloading() 
        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......");
                //alert(xmlhttp.readystate)
                if(xmlhttp.readystate==4)
                {    if(xmlhttp.status==200)
                    {    if(obj1!=obj2){fclose(obj1);};
                        echo(obj2,xmlhttp.responsetext);
                        showloading() 
                    }
                }            
        }
}
function postdata(url,obj,data)
{       var rnd=math.random()
        var xmlhttp=createxmlhttp();
        if(!xmlhttp)
        {
            alert("你的浏览器不支持xmlhttp！！");
            return;
        }
        showloading() 
        xmlhttp.open("post", url, true);
        xmlhttp.onreadystatechange=requestdata;
        xmlhttp.setrequestheader("content-type","application/x-www-form-urlencoded");
        xmlhttp.send(data);
        function requestdata()
        {    fopen(obj);
            echo(obj,"正在提交数据，请稍等......");
            if(xmlhttp.readystate==4)
            {    if(xmlhttp.status==200)
                {
                    echo(obj,xmlhttp.responsetext);
                    reget(rnd);
                    settimeout("echo('showresult','')",2000);
                    echo('message','')
                    showloading() 
                }
            }
        }
}
function ltrim(str)
{
  if (str.charat(0) == " ")
  {
    //如果字串左边第一个字符为空格
    str = str.slice(1);//将空格从字串中去掉
    //这一句也可改成 str = str.substring(1, str.length);
    str = ltrim(str);    //递归调用
  }
  return str;
}

//去掉字串右边的空格
function rtrim(str)
{
  var ilength;

  ilength = str.length;
  if (str.charat(ilength - 1) == " ")
  {
    //如果字串右边第一个字符为空格
    str = str.slice(0, ilength - 1);//将空格从字串中去掉
    //这一句也可改成 str = str.substring(0, ilength - 1);
    str = rtrim(str);    //递归调用
  }
  return str;
}

//去掉字串两边的空格
function trim(str)
{
  return ltrim(rtrim(str));
}

function f(obj)
{
    return trim(eval("document.ajax_post."+obj+".value"));
    //return trim($(obj).value);
}

function savereply()
{    if(f("username")=="")
    {    alert("请填写用户名");
        return false;
    }
    if(f("message")=="")
    {    alert("内容不可為空");
        return false;
    }
    var validate,password,log_diskey=0,log_disurl=0,log_dissm=0
    validate=""
    password=""
    if(document.ajax_post.log_diskey.checked){
        log_diskey=f("log_diskey")
        }
    if(document.ajax_post.log_disurl.checked){
        log_disurl=f("log_disurl")
        }
    if(document.ajax_post.log_dissm.checked){
        log_dissm=f("log_dissm")
        }
    if((typeof eval(document.ajax_post.validate))!="undefined"){
        if(f("validate")=="")
        {    alert("请填写验证码");
            return false;
        }else{
            validate=f("validate");
        }
    }    
    if((typeof eval(document.ajax_post.password))!="undefined"){
        password=f("password");
    }
    data="username="+escape(f("username"))+"&password="+escape(password)+"&validate="+escape(validate)+"&log_dissm="+escape(log_dissm)+"&log_disurl="+escape(log_disurl)+"&log_diskey="+escape(log_diskey)+"&message="+escape(f("message"))+"&logid="+escape(f("logid"))+"&action="+escape(f("action"));
    //alert(data);
    postdata("wbc_blogcomm.asp","showresult",data);
    return true;
}