我有一个搜索页面，用户可以根据他们可以从下拉列表中选择的类别来搜索项目。当我选择一个类别时，它会显示数据和下一页，但是当我单击下一页时，该页面不显示任何结果。请帮忙
<?php
include("scripts/connection.php");
session_start();
if (empty($_SESSION["username"])) {
header("Location:login.php");
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Search Posts</title>
<link rel="stylesheet" href="style.css" type="text/css" media="all" />
</head>
<body>
<div class="main-menu">
<ul id="menu">
<li><a href="mainhome.php">Home</a></li>
<li><a href="itempost.php">New Post</a></li>
<li><a href="yourpost.php">Your Posts</a></li>
<li id="active"><a href="Search.php">Search Posts</a></li>
<li class="log"><a href="scripts/logout.php">Log Out</a></li>
<li class="log"><a href="account.php">Account</a></li>
</ul>
</div>
<div id="header"><img src="Images/header.gif"/></div>
<div id="sidebar"><h2><u>Posts</u></h2><p/>
<form method="POST" name="SearchForm" action="search.php">
<table id="mainhomeform">
<tr>
<td>Select a category to search through:<p/>
<select name="SearchCategory" class="searchlist" tabindex="1">
<option value="<?php if(isset($searchcategory)){echo $searchcategory;}else{echo "Uncategorized";}?>"><?php if(isset($searchcategory)){echo $searchcategory;}else{echo "Uncategorized";}?></option>
<option value="Clothing">Clothing</option>
<option value="Electronics">Electronics</option>
<option value="Furniture">Furniture</option>
<option value="Stationary">Stationary</option>
</select>
</td>
</tr>
<tr>
<td>
<input name="search" type="submit" class="wbutton" tabindex="3" value="Search" />
</td>
</tr>
</table>
</form>
</div>
<div id="content"><h2><img src="Images/posts.gif"/></h2>
<?php
if(isset($_POST['search'])) {
$searchcategory = $_POST['SearchCategory'];
$searchbutton = $_POST['search'];
$search = "SELECT * FROM items WHERE Category='$searchcategory' ORDER BY PostDate DESC";
$select = mysql_query($search);
$nr = mysql_num_rows($select);
if ($nr>0) {
if (isset($_GET['pn'])) {
$pn = preg_replace('#[^0-9]#i', '', $_GET['pn']);
} else {
$pn = 1;
}
$itemsPerPage = 5;
$lastPage = ceil($nr / $itemsPerPage);
if ($pn < 1) {
$pn = 1;
} else if ($pn > $lastPage) {
$pn = $lastPage;
}
$centerPages = "";
$sub1 = $pn - 1;
$sub2 = $pn - 2;
$add1 = $pn + 1;
$add2 = $pn + 2;
if ($pn == 1) {
$centerPages .= ' <span class="pagenumbers">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
} else if ($pn == $lastPage) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagenumbers">' . $pn . '</span> ';
} else if ($pn > 2 && $pn < ($lastPage - 1)) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub2 . '">' . $sub2 . '</a> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagenumbers">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add2 . '">' . $add2 . '</a> ';
} else if ($pn > 1 && $pn < $lastPage) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagenumbers">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
}
$limit = 'LIMIT ' .($pn - 1) * $itemsPerPage .',' .$itemsPerPage;
$select2 = mysql_query("SELECT * FROM items WHERE Category='$searchcategory' ORDER BY PostDate DESC $limit");
$select2_array = array();
$paginationDisplay = "";
if ($lastPage != "1") {
if ($pn != 1) {
$previous = $pn - 1;
$paginationDisplay .= ' <a class="button" href="' . $_SERVER['PHP_SELF'] . '?pn=' . $previous . '"> Back</a> ';
}
$paginationDisplay .= '<span class="pagenumbers">' . $centerPages . '</span>';
if ($pn != $lastPage) {
$nextPage = $pn + 1;
$paginationDisplay .= ' <a class="button" href="' . $_SERVER['PHP_SELF'] . '?pn=' . $nextPage . '"> Next</a> ';
}
}
for ($count=0; $row = mysql_fetch_array($select2);$count++) {
$select2_array[$count] = $row;
echo "<table id='home'>";
foreach($select2_array as $itemshome);
echo "<tr>";
echo "<td class='title'>". $itemshome ['Title']."</td>";
echo "<td class='rf'>". $itemshome ['PostDate']."<br/>".$itemshome ['Category']."</td>";
echo "<hr>";
echo "</tr>";
echo "<tr>";
echo "<td colspan='3'>"."<img src='$itemshome[Image1]' class='pic' alt='userimage' />";
echo "<img src='$itemshome[Image2]' class='pic' alt='userimage' />";
echo "<img src='$itemshome[Image3]' class='pic' alt='userimage' />"."</td>";
echo "</tr>";
echo "<tr>";
echo "<td colspan='3'>"."<textarea name='Description' type='text' class='description' tabindex='2' readonly >".$itemshome ['Description']."</textarea>"."</td>";
echo "</tr>";
echo "</tr>";
}
echo "</table>";
echo "$paginationDisplay";
} else {
$empty = '<div class="error">That category is empty.</div>';
echo $empty;
}
}
?>
<div class="footer">
<hr/>
Copyright ©<br/>Designed Using XHTML 1.1
<p id="rf">Designed by Mutondo Sitemba</p>
</div>
</div>
</body>
</html>