email code

<?php    //表单数据    $to = $_POST['to'];    $from = $_POST['from'];    $cc =  $_POST['cc'];    $title = $_POST['title'];    $message = $_POST['message'];    $submit = $_POST['submit'];        //$submit为HMTL主页面中的提交按钮    if($submit)    {        //$to为由HMTL页面传入的收信人地址        if(!$to)        {            echo "<p align = center><font color = red size = 4>                    <b>收件人地址不能为空！<br></b>请点击此处                    <a href = javascript:history.go(-1);>返回</a></font></p>";            exit();        }                //$title为由HTML页面传入的信件标题        if(!$title) $title = "";                //$message为由HTML页面传入的正文内容        if(!$message) $message = "";                //$from为由HMTL页面传入的发信人地址        if($from)        {            $from = "From:$from \n";            $reply = "Reply-To:$from \n";        }        else        {            $from = "";        }                //$cc为由HTML页面传入的抄送信息        if($cc)        {            $cc = "CC:$cc";        }        else        {            $cc = "";        }                if(@mail($to,$title,$message,$from,$reply,$cc))        {            echo "<p align = center><font color = red size = 4><b>                你的邮件发送成功！<br></b>请点击此处                <a href = javascript:history.go(-1);>返回</a></font></p>";            exit();        }        else        {            echo "<p align = center><font color = red size = 4>                <b>对不起！你的邮件发送不成功！<br></b>请点击此处                <a href = javascript:history.go(-1);>返回</a></font></p>";            exit();        }    }?>