<?php      header("content-type:text/html;charset=utf-8");     //数据库连接     $conn = mysql_connect("localhost", "root", "111") or die("not connnected : ".mysql_error());     mysql_select_db("test", $conn);     mysql_query("set names utf8");     //查询共有多少行数据     $sql1 = "select count(*) from user";     $ret1 = mysql_query($sql1);     $row1 = mysql_fetch_row($ret1);     $tot = $row1[0];     //每页多少行数据     $length = 5;          //总页数      $totpage = ceil($tot / $length);     //当前页数     $page = @$_GET['p'] ? $_GET['p'] : 1;     //limit 下限     $offset = ($page - 1) * $length;     echo "<center>";     echo "<h2>php padding</h2>";     echo "<table width='700px' border='1px' >";     echo "<tr>";     echo "<th>ID</th>";     echo "<th>USER</th>";     echo "<th>PASS</th>";     echo "</tr>";     //将查询出来的数据用表格显示     $sql2 = "select * from user order by id limit {$offset}, {$length}";     $ret2 = mysql_query($sql2);     while ($row2 = mysql_fetch_assoc($ret2)) {         echo "<tr>";         echo "<td>{$row2['id']}</td><td>{$row2['name']}</td><td>{$row2['pass']}</td>";         echo "</tr>";     }     echo "</table>";     //上一页和下一页     $prevpage = $page - 1;     if ($page >= $totpage) {         $nextpage = $totpage;     } else {         $nextpage = $page + 1;     }     //跳转     echo "<h3><a href='index.php?p={$prevpage}'>上一页</a>|<a href='index.php?p={$nextpage}'>下一页</a></h3>";     echo "</center>";