php实现搜索多关键词高亮显示程序代码

<?php
 include 'conn.php';
 ?>
 
 <table width=500 align="center">
     <form action="" method="get">
     <tr>
         <td>关键字：<input type="text" name="keyWord" />
         <input type="submit" value="搜索" /></td>
     </tr>
     </form>
 </table>
 
 <table width=500 border="0" align="center" cellpadding="5"
     cellspacing="1" bgcolor="#add3ef">
     <?php
     //关键字不为空的时候才执行相关搜索
     if($_GET['keyWord']){
     //用空格符把关键字分割开
     $key=explode(' ', $_GET[keyWord]);
     $sql="select * from message where title like '$key[0]' or title like '$key[1]' or content like '$key[0]' or content like '%$key[1]%'";
     $query=mysql_query($sql);
     while ($row=mysql_fetch_array($query)){
         //替换关键字，并且把关键字高亮显示
         $row[title]=preg_replace("/$key[0]/i", "<font color=red><b>$key[0]</b></font>", $row[title]);
         $row[title]=preg_replace("/$key[0]/i", "<font color=red><b>$key[1]</b></font>", $row[title]);
         $row[content]=preg_replace("/$key[0]/i", "<font color=red><b>$key[0]</b></font>", $row[content]);
         $row[content]=preg_replace("/$key[1]/i", "<font color=red><b>$key[1]</b></font>", $row[content]);
         ?>
 
     <tr bgcolor="#eff3ff">
         <td>标题：<font color="black"><?=$row[title]?></font> 用户：<font color="black"><?=$row[user] ?></font>
         <div align="right"><a href="preEdit.php?id=<?=$row[id]?>">编辑</a>&nbsp;&nbsp;|&nbsp;&nbsp;<a
             href="delete.php?id=<?=$row[id]?>">删除</a></div>
         </td>
     </tr>
     <tr bgColor="#ffffff">
         <td>内容：<?=$row[content]?></td>
     </tr>
     <tr bgColor="#ffffff">
         <td>
         <div align="right">发表日期：<?=$row[lastdate]?></div>
         </td>
     </tr>
     <?php }
     }
     ?>
 </table>