php 多关键字 高亮显示实现代码

<?php
$conn = @ mysql_connect("localhost", "root", "") or die("数据库链接错误");
mysql_select_db("form", $conn);
mysql_query("set names 'gbk'");
?>

<?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=<?=$row[id]?>">编辑</a>  |  <a
href="delete.php?id=<?=$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>

//用空格符把关键字分割开
$key=explode(' ', $_GET[keyWord]);