首先，我是PHP和使用Forms的新手，但我正在边学习边学习！第二，我知道这已经被报道了很多次，但我就是不能让它为我工作！这可能只是我忽略的东西。。。
我有一个表单，有1个搜索字段和3个提交按钮。根据所选的按钮，查询将在数据库中查找3个不同搜索中的一个。很简单。。。
http://1karaokedj.com
<input name="searchterm" type="search" placeholder="Enter Search Terms Here" class="search" />
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Artist Search" />
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Title Search" />
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Disc ID Search" />
<?php if(isset($_SESSION['searchterm'])) {
if(($_SESSION['searchterm']!="")) {
switch ($_POST['searchbtn']) {
case 'Artist Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Artist like '%$searchterm%' limit 100");
break;
case 'Title Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Title like '%$searchterm%' limit 100");
break;
case 'Disc ID Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Disc like '%$searchterm%' limit 100");
break;
}
if(mysqli_num_rows($searchresults) > 0) {
...
}}}?>
这总是返回未找到的记录。如果我添加一个默认情况，那么它就起作用了print_r（$_POST）；return"Array（）"
以下是完整的代码，以防问题出现在其他地方：
<?php
include("connect.php");
require_once 'Mobile_Detect.php';
$detect = new Mobile_Detect;
ini_set('session.cookie_lifetime',900);
ini_set('session.gc_maxlifetime',900);
session_start();
if(isset($_POST['searchbtn'])) {
$_SESSION['searchterm']=$_POST['searchterm'];
if(($_SESSION['searchterm'])!="") { header("location:index.php"); }
else { echo "<script> alert('Please enter something to search for') </script>"; }
}
?>
<html>
<head>
<title>1KaraokeDJ.com Search</title>
<link rel="stylesheet" href="style.css" />
</head>
<body>
<div class="container">
<form method="post">
<p><code>
<img src="top1.jpg" /><br>
<?php if ($detect->isMobile()) { echo("Mobile Device Detected"); } else { echo("Desktop Browser Detected"); } ?>
</code></p>
<p>
<?php if(isset($_SESSION['searchterm'])) { ?>
<input name="searchterm" type="search" value="<?php echo $_SESSION['searchterm'];?>" class="search" />
<?php } else { ?>
<input name="searchterm" type="search" placeholder="Enter Search Terms Here" class="search" />
<?php } ?>
</p>
<p>
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Artist Search" />
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Title Search" />
<input name="searchbtn" type="submit" id="searchbtn" class="searchbutton" value="Disc ID Search" />
</p>
<hr style="width:100%">
<?php if(isset($_SESSION['searchterm'])) {
if(($_SESSION['searchterm']!="")) {
$searchterm=strtoupper($_SESSION['searchterm']);
print_r($_POST);
switch ($_POST['searchbtn']) {
case 'Artist Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Artist like '%$searchterm%' limit 100");
break;
case 'Title Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Title like '%$searchterm%' limit 100");
break;
case 'Disc ID Search':
$searchresults=$db->query("select * from 1KaraokeDJ where Disc like '%$searchterm%' limit 100");
break;
}
if(mysqli_num_rows($searchresults) > 0) {
while($descri=mysqli_fetch_object($searchresults)) { ?>
<div class="reslt">
<h3 id="results">
<?php
echo str_ireplace($searchterm, '<span class="highlight">'.$searchterm."</span>", $descri->Artist);
echo " - ";
echo str_ireplace($searchterm, '<span class="highlight">'.$searchterm."</span>", $descri->Title);
?>
</h3>
<p class="Description">
<?php
echo str_ireplace($searchterm, '<span class="highlight">'.$searchterm."</span>", $descri->Brand);
echo " - ";
echo str_ireplace($searchterm, '<span class="highlight">'.$searchterm."</span>", $descri->Disc);
echo " - ";
echo $descri->Track;
?>
<p>
<hr>
</div>
<?php } ?>
<div class="reslt">
<h3 id="results"><?php echo mysqli_num_rows($searchresults) ?> Results</h3>
<?php if(mysqli_num_rows($searchresults) >= 100) { ?>
<p class="Description highlight">Showing Up To 100 Results<br>Try Refining Your Search</p><hr>
<?php } ?>
</div>
<?php } else { ?>
<div class="reslt">
<h3 id="results">Nothing Found!</h3>
<p class="Description highlight">Try Changing Your Search Terms<p><hr>
</div>
<?php } } } ?>
</form>
<code>This site is in testing... Things may change anytime<br>and many things may not work for a while!</code>
</div>
</body>
</html>
这是因为下一行在提交表单时重定向。重定向时不保留POST值。因此，$_POST['searchbtn']是空的，并且在switch语句中它转到default的情况。
header("location:index.php");
注释头重定向，它应该可以工作。
更新代码：
if(isset($_POST['searchbtn'])) {
$_SESSION['searchterm']=$_POST['searchterm'];
if(($_SESSION['searchterm'])!="") { /*header("location:index.php");*/ }
else { echo "<script> alert('Please enter something to search for') </script>";}
}