上一次我们研究了guest.php文件.具体的问题还要求读者朋友自己深入的去实践,而且需要一些工具书来学习,如果您一点php的知识都没有,笔者奉劝您就不要想下看了,笔者没有太多的时间和篇幅去逐句探究一个php文件的用途和意义.好的,接下来我们来作edit.php这个文件. 
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//edit.php 
<? 
   if ($Submit) 
   { 
if ($SavePassword=="on") 
{setcookie("TxtPassword","$TxtPassword",time() 30*24*3600);} 
else 
{setcookie("TxtPassword");} 
   } 
?> 
<html> 
<style type=text/css> 
Td {FONT-SIZE: 10pt;} 
TEXTAREA 
{ 
FONT-FAMILY: "宋体"; 
FONT-SIZE: 10pt; 
} 
</style> 
<head> 
<meta http-equiv="Content-Language" content="zh-cn"> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<title>修改留言</title> 
<? 
require("sys.php"); 
function readvalue($tags,$tage) 
{ 
global $message,$long,$reply; 
$StrStart=strlen(strstr($message,$tags))-strlen($tags);//去除标记后变量所在字串的起始位置. 
$StrEnd=strlen(strstr($message,$tage)); 
$len=$StrStart-$StrEnd; 
$StrStart=$long-$StrStart;//起始字符. 
$StrString=substr($message,$StrStart,$len); 
return $StrString; 
} 
function save($record) 
{ 
global $TxtContent,$TxtEmail,$TxtHomepage,$TxtEmail,$TxtName,$TxtFrom,$TxtReply,$REMOTE_ADDR,$guestfile; 
$content=file($guestfile,"r"); 
$space = " "; 
$time = date(Y年m月d日H小时i分); 
$ip=$REMOTE_ADDR; 
$TxtReply=StripSlashes($TxtReply); 
$TxtContent=StripSlashes($TxtContent); 
$TxtContent=htmlspecialchars($TxtContent); 
$TxtContent=check_strlen_long($TxtContent); 
$TxtContent=nl2br($TxtContent); 
$Wcontent = "<tr><td><font color=#AB00E1>留言内容:</font><br><!--content>$TxtContent<!--endcontent> "; 
$Wcontent=$Wcontent."<br><font color=#6633FF>留言人大名:</font><!--name>$TxtName<!--endname> "; 
if ($TxtEmail !="") 
{$Wcontent=$Wcontent."<br><font color=#9900CC>电子信箱</font><a href="mailto:$TxtEmail"><!--email>$TxtEmail<!--endemail></a>"."$space";} 
if ($TxtHomepage !="http://") 
{$Wcontent=$Wcontent."<font color=#9900CC>主页:</font>$TxtHompage<a href="$TxtHomepage" target=new><!--homepage>$TxtHomepage<!--endhomepage></a>";} 
$Wcontent=$Wcontent."<br><font color=#0000FF>时间:$time 来自:<!--from>$TxtFrom<!--endfrom> ".$ip."</font>"; 
$Wcontent=ereg_replace(chr(10),"",$Wcontent); 
$Wcontent=$Wcontent."<hr size=1></td></tr>"; 
$TxtReply=ereg_replace(chr(10),"",$TxtReply); 
$WContent=$Wcontent.$TxtReply."n"; 
$count=count($content); 
$fp=fopen($guestfile,"w"); 
for ($i=0;$i<$count;$i  ) 
{ 
 if ($i==$record-1) 
  {$content[$i]=$WContent;} 
fputs($fp,$content[$i]); 
} 
fclose($fp); 
} 
$content=file($guestfile,"r"); 
$message=$content[$record-1]; 
$long=strlen($message); 
$txtcontent=readvalue('<!--content>','<!--endcontent>'); 
$txtname=readvalue('<!--name>','<!--endname>'); 
$txtfrom=readvalue('<!--from>','<!--endfrom>'); 
$txtemail=readvalue('<!--email>','<!--endemail>'); 
$txthomepage=readvalue('<!--homepage>','<!--endhomepage>'); 
$txtcontent=strip_tags($txtcontent); 
$tags="<!--reply>"; 
$txtreply=strstr($message,$tags); 
$txtreply=ereg_replace(""",""",$txtreply); 
if ($Submit) 
  { 
  if ($TxtPassword==$managepwd) 
  { 
  if ($TxtName!="" and $TxtContent!="") 
    { 
  save($record); 
  echo "<meta http-equiv=Refresh content="1;url=guest.php">"; 
  exit; 
    }else {$errorm="留言人姓名和内容必填!!";} 
  } 
  else {$errorm="密码错误,只有管理员有权修改!!";} 
  } 
?> 
</head> 
<body bgcolor="#FFFFFF" background="back.gif"> 
<? include('head.htm');?> 
<div align="center"> 
  <center> 
    <table border="1" width="68%" height="31" cellspacing="0" cellpadding="7" bordercolor="#E3E3E3"> 
     <form action="edit.php" method=post> 
     <? 
     if ($errorm and $Submit) 
     { 
        echo"<tr>";  
        echo"<td height=40 colspan=4>"; 
        echo"<font color=red>出错了,</font>$errorm"; 
        echo"</td>"; 
        echo"</tr>"; 
     } 
     ?> 
        <tr>  
          <td width="18%" height="37" bgcolor="#f0f0f0"><font color="#000000">留言大名</font></td> 
          <td width="39%" height="37" bgcolor="#FFFFFF">  
            <input type="text" name="TxtName" size="26" value=<?echo "$txtname"?>> 
             </td> 
          <td width="11%" height="37" bgcolor="#f0f0f0"><font color="#000000">来自</font></td> 
          <td width="32%" height="37" bgcolor="#FFFFFF">  
            <input type="text" name="TxtFrom" size="20" value=<?echo "$txtfrom"?>> 
          </td> 
      </tr> 
      <tr>  
          <td width="18%" height="31" bgcolor="#f0f0f0"><font color="#000000">主页地址</font></td> 
          <td width="39%" height="31" bgcolor="#FFFFFF">  
            <input type="text" name="TxtHomepage" size="26" value=<?echo "$txthomepage"?>> 
          </td> 
          <td width="11%" height="31" bgcolor="#f0f0f0"><font color="#000000">Email</font></td> 
          <td width="32%" height="31" bgcolor="#FFFFFF">  
            <input type="text" name="TxtEmail" size="20" value=<?echo "$txtemail"?>> 
          </td> 
      </tr> 
        <tr bgcolor="#FFFFFF">  
          <td height="31" colspan="4"><font color="#000000">留言内容</font></td> 
      </tr> 
        <tr bgcolor="#f0f0f0">  
          <td height="105" colspan="4" valign="middle" align="center">  
            <textarea rows="6" name="TxtContent" cols="50" wrap="VIRTUAL"><? echo "$txtcontent"?> 
          </textarea> 
        </td> 
      </tr> 
        <tr bgcolor="#FFFFFF">  
          <td height="40" colspan="4" valign="middle" align="center"> <font color="#000000">修改密码</font>  
            <input type="password" name="TxtPassword" size="10" value=<?echo "$TxtPassword"?>> 
            <font color="#000000">是否保存密码</font>  
            <input type="checkbox" name="SavePassword" value="on" checked> 
          <input type=hidden name=record value=<? echo "$record"?>> 
          <input type="submit" value="我要修改了" name="Submit"> 
        </td> 
      </tr> 
      <? echo "$txtreply"?> 
       <input type=hidden name=TxtReply value="<? echo "$txtreply" ?>"> 
      </form> 
    </table> 
  </center> 
</div> 
<?include('bottom.htm');?> 
</body> 
</html> 
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该注明的地方我已作了诠释.php可以嵌入html代码中,这样写起代码很惬意. 
待续...