Example of PHP using regular expressions to filter illegal strings-PHP Tutorial-php.cn

Example of PHP using regular expressions to filter illegal strings

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Release： 2023-03-29 19:00:01

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This article mainly introduces PHP's use of regular expressions to implement the function of filtering illegal strings. Combined with the example of the message board data submission function, it analyzes the related operation skills of PHP using the regular expression preg_replace function to perform regular string replacement. Friends who need it can Refer to the example below

This article describes how PHP uses regular expressions to implement the function of filtering illegal strings. Share it with everyone for your reference, the details are as follows:

1. Code

1, index.php

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>过滤留言板中的非法字符</title>
<style type="text/css">
<!--
body {
  margin-left: 0px;
  margin-top: 0px;
  margin-right: 0px;
  margin-bottom: 0px;
}
-->
</style></head>
<body>
<table width="1002" height="585" border="0" align="center" cellpadding="0" cellspacing="0">
 <tr>
  <td width="379" height="226"> </td>
  <td width="445"> </td>
  <td width="178"> </td>
 </tr>
   <form id="form1" name="form1" method="post" action="index_ok.php">
 <tr>
  <td height="260"> </td>
  <td align="center" valign="top"><table width="430" border="1" cellpadding="1" cellspacing="1" bordercolor="#FFFFFF" bgcolor="#99CC67">
   <tr>
    <td width="81" height="30" align="right" bgcolor="#FFFFFF">发布主题：</td>
    <td width="307" align="left" bgcolor="#FFFFFF"><input name="title" type="text" id="title" size="30" /></td>
   </tr>
   <tr>
    <td align="right" bgcolor="#FFFFFF">发布内容：</td>
    <td align="left" bgcolor="#FFFFFF"><textarea name="content" cols="43" rows="13" id="content"></textarea></td>
   </tr>
  </table></td>
  <td> </td>
 </tr>
 <tr>
  <td height="99"> </td>
  <td align="center" valign="top"><table width="315" height="37" border="0" cellpadding="0" cellspacing="0">
   <tr>
    <td width="169" align="center"><input type="image" name="imageField" src="images/bg1.JPG" /></td>
    <td width="146" align="center"><input type="image" name="imageField2" src="images/bg3.JPG" onclick="form.reset();return false;" /></td>
   </tr>
  </table></td>
  <td> </td>
 </tr>
   </form>
</table>
</body>
</html>

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2. index_ok.php

<?php
$title=$_POST[title];
$content=$_POST[content];
$str="****";
$titles = preg_replace("/(黑客)|(抓包)|(监听)/",$str,$title);
$contents = preg_replace("/(黑客)|(抓包)|(监听)/",$str,$content);
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>过滤留言板中的非法字符</title>
<style type="text/css">
<!--
body {
  margin-left: 0px;
  margin-top: 0px;
  margin-right: 0px;
  margin-bottom: 0px;
}
.STYLE1 {
  font-size: 12px;
  color: #855201;
}
-->
</style></head>
<body>
<table width="1002" height="585" border="0" align="center" cellpadding="0" cellspacing="0">
 <tr>
  <td width="400" height="226"> </td>
  <td width="406"> </td>
  <td width="196"> </td>
 </tr>
   <form id="form1" name="form1" method="post" action="index_ok.php">
 <tr>
  <td height="260"> </td>
  <td align="left" valign="top"><p class="STYLE1">发布主题：<?php echo $titles;?></p>
   <p class="STYLE1">发布内容：<?php echo $contents;?></p></td>
  <td> </td>
 </tr>
 <tr>
  <td> </td>
  <td align="center" valign="top"> </td>
  <td> </td>
 </tr>
 </form>
</table>
</body>
</html>

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2. Running results

Post topic: ****
Post content: **** customer **** package

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