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 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;
}
}

<?php
header('Content-Type:text/html;charset=GB2312');//避免输出中文乱码，linux下不需要
$username=trim($_GET['username']);
$newfourm=trim($_GET['newfourm']);
$id=$_GET['id'];
$time=date("Y-m-d");
include('inc/config.inc.php');
include('inc/dbclass.php');
$db=new db;//从数据库操作类生成实例
$db->mysql($dbhost,$dbuser,$dbpassword,$dbname);//调用连接参数函数
$db->createcon();//调用创建连接函数
$addsql="insert into cr_fourm values(0,'$newfourm','$username','$time',$id)";
$db->query($addsql);
echo"<img src=images/pass.gif> <font color=red>评论已成功发表！</font>";
//echo $addsql;
$db->close();//关闭数据库连接
?>

<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center"><?php echo $rows_p[p_info];?></td>
</tr>
<tr>
<td align="center"><br><br><iframe frameborder="0" scrolling="auto" src="showfourm.php?picid=<?=$id;?>" style=HEIGHT:250px;VISIBILITY:inherit;WIDTH:98%;Z-INDEX:2 ></iframe>
</td>
</tr>
<tr>
<td align="center"><br><br>
<div align="center" id="result"></div>
<form name="fourm">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="25"> 快速发表评论<span class="STYLE1">（必须先登陆）用户名：
<input name="username" type="text" value="<?=$username?>" readonly>
</span></td>
</tr>
<tr>
<td height="32" align="center" valign="middle"><textarea name="newfourm" class="f" id="newfourm"></textarea></td>
</tr>
<tr>
<td height="32"> <input name="submit" type="button" value="发表评论" onClick="checkfourm('result')">
<input name="reset" type="reset" id="reset" value="重新填写">
<input name="id" type="hidden" id="id" value="<?php echo"$id";?>"></td>
</tr>
</table>
</form>
</td>
</tr>
</table>