PHP分页代码

头部调用
 <?
require('conn.php');
$sql1="select id from news";
$query1=mysql_query($sql1,$conn);
$sun_num=mysql_num_rows($query1);
$gs=20;
$page_num=ceil($sun_num/$gs);
include("../subpage.php");
//传过来的页数参数
$PB_page=$_GET['PB_page'];
if ($PB_page==1 or empty($PB_page)){
$a=0;
}else{
$a=(($PB_page-1)*$gs);
}
?>
HTML部分代码
<div style="margin-top:10px;" mce_style="margin-top:10px;">
<table width="99%" border="0" cellspacing="0" cellpadding="0">
<form id="form1" name="form1" method="get" onsubmit="return checkkey()"> <tr>
<td width="9%" height="25" align="center">
<span style="color:#067098; font-weight:bold" mce_style="color:#067098; font-weight:bold">文章搜索：</span> </td>
<td width="25%" align="left"><input name="key" type="text" class="txt" id="key" size="40"/></td>
<td width="66%" align="left"><input type="submit" name="Submit" value="搜 索" /></td>
</tr>
</form>
</table>
<table width="99%" border="0" align="center" cellpadding="0" cellspacing="1">
<tr>
<td height="30" colspan="6" bgcolor="#FFFFFF" class="title" style="border-top:1px #B8D3E1 solid; border-bottom:1px #F7AC1B dashed" mce_style="border-top:1px #B8D3E1 solid; border-bottom:1px #F7AC1B dashed">新闻列表</td>
</tr>
<tr>
<td width="6%" height="25" align="center" bgcolor="#B5E9FF">ID</td>
<td width="63%" height="25" align="center" bgcolor="#B5E9FF">新闻标题</td>
<td width="8%" align="center" bgcolor="#B5E9FF">作者</td>
<td width="13%" align="center" bgcolor="#B5E9FF">添加时间</td>
<td colspan="2" align="center" bgcolor="#B5E9FF">操 作</td>
</tr>
<?
if (!$_GET[key]){

$sql="SELECT * from news order by id desc limit $a,$gs";
}else{