高手帮我看这两行代码的意思
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>添加数据</title>
<link rel="stylesheet" type="text/css" href="mystyle.css">
</head>
<body>
<center>
<table width="799" border="0" cellpadding="0" cellspacing="0">
<tr>
<td height="106" background="images/banner.jpg"> </td>
</tr>
<tr>
<td>
<table width="100%" height="27" border="0" cellpadding="0" cellspacing="0" background="images/link.jpg">
<tr>
<td width="243" align="center" valign="middle"><b>
<?php
echo date("Y-m-d")." ";
echo date(l);
?>
</b></td>
<td width="90" align="center" valign="middle"><a href="index.php
?action=show" class="a">浏览目录</a></td>
<td width="94" align="center" valign="middle"><a href="index.php?
action=insert" class="a">添加图书</a></td>
<td width="94" align="center" valign="middle"><a href="#" class="a">简单查询</a></td>
<td width="91" align="center" valign="middle"><a href="#" class="a">高级查询</a></td>
<td width="94" align="center" valign="middle"><a href="#" class="a">分组统计</a></td>
<td width="93" align="center" valign="middle"><a href="#" class="a">退出系统</a></td>
</tr>
</table>
</td>
</tr>
</table>
<table width="799" height="300" border="0" cellpadding="0" cellspacing="0">
<tr>
<td align="center" valign="middle">
<?php
$conn = mysql_connect("localhost","root","root");
mysql_query("set names gb2312");
mysql_select_db("db_mingrisoft");
//浏览图书
if (($action == null) or ($_GET[action] == "show")){
?>
<form name="form1" id="form1" method="post">
<table width="90%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="5%" height="25" class="top">id</td>
<td width="30%" class="top">书名</td>
<td width="10%" class="top">价格</td>
<td width="20%" class="top">出版时间</td>
<td width="10%" class="top">类别</td>
<td width="10%" class="top">操作</td>
</tr>
<?php
$sqlstr = "select * from tb_mrbook order by id";
$result = mysql_query($sqlstr,$conn);
while ($rows = mysql_fetch_row($result)){
echo "<tr>";
for($i = 0; $i < count($rows); $i++){
echo "<td height='25' align='center' class='m_td'>".$rows[$i]."</td>";
}
echo "<td class='m_td'><a href='#'>修改</a>/