我是一名认证新手，所以如果我的问题对你来说听起来很愚蠢，请耐心等待。
你好。我试图使用PHP获取html<input type="hidden">的值。隐藏元素的值从Javascript传递，我需要使用php echo显示该隐藏元素的值。根据我的理解（我希望我理解正确），当您执行$description = isset($_GET['description']) ? $_GET['description'] : null;和<input type="hidden" id="description" value="<?php echo $description; ?>" />之类的操作时，您可以使用<?php echo $_GET['description']; ?>访问/显示隐藏元素的值，但我是得到一个未定义的索引：description。我是一个总菜鸟，所以我真的很困惑。我希望我的问题不那么令人困惑。无论如何，我非常愿意回答探究性问题。
顺便说一句，这是代码：
index.php
<?php include('functions.php'); ?>
<?php
$yr = isset($_GET['year_list']) ? $_GET['year_list'] : null;
$evnt = isset($_GET['event_list']) ? $_GET['event_list'] : null;
$description = isset($_GET['description']) ? $_GET['description'] : null;
?>
<html>
<head>
<script type="text/javascript" src="myscripts.js"></script>
<style type='text/css'>
#show_description {
min-height: 100px;
min-width: 500px;
max-height: 100px;
max-width: 500px;
background-color: #000;
color: #fff;
padding: 10px;
}
</style>
</head>
<body onload="check_year_event();">
<div>
<form name="myform" action="index.php" method="get" >
<input type="hidden" id="hidden_year_list" value="<?php echo $yr; ?>" />
<input type="hidden" id="hidden_event_list" value="<?php echo $evnt; ?>" />
<input type="hidden" id="description" value="<?php echo $description; ?>" />
Select Year: <?php echo hspacer(1); ?>
<select id="year_list" name="year_list" onchange="check_year_event();" >
<?php
for($year = (date('Y') - 100); $year <= (date('Y') + 100); $year++ ) {
if ($year == date('Y')) echo "<option value='$year' name='$year' selected='' >" . $year . "</option>";
else echo "<option value='$year' name='$year' >" . $year . "</option>";
}
?>
</select>
<?php echo hspacer(5); ?>
Select Event: <?php echo hspacer(1); ?>
<select id="event_list" name="event_list" onchange="check_year_event();" >
<?php
$events = array("Karate Tournament", "Beauty Pageant", "Film Festival", "Singing Contest", "Wedding");
foreach($events as $event) echo "<option value='$event' name='$event' >" . $event . "</option>";
?>
</select>
<?php echo vspacer(2); echo hspacer(22); ?>
<input type="submit" id="send_notice" value="Send Notice" onclick="check_year_event(); return false; "/>
</form>
</div>
<div id="show_description" >
<?php echo $_GET['description']; ?>
</div>
</div>
</body>
</html>
functions.php
<?php
function hspacer($num_of_spaces) {
$spaces = "";
if ($num_of_spaces > 0) for($i=0; $i<$num_of_spaces; $i++ ) $spaces .= " ";
return $spaces;
}
function vspacer($num_of_linefeeds) {
$linefeeds = "";
if ($num_of_linefeeds > 0) for($i=0; $i<$num_of_linefeeds; $i++ ) $linefeeds .= "<br />";
return $linefeeds;
}
?>
myscripts.js
function create2DArray(row, col){
var array2D = new Array(row);
for (var i = 0; i < row; i++) {
array2D[i] = new Array(col);
}
return array2D;
}
function check_year_event() {
var years_and_events = create2DArray(10, 3);
years_and_events[0][0] = 2001;
years_and_events[0][1] = "Karate Tournament";
years_and_events[0][2] = "Annual karate tournament held globally";
years_and_events[1][0] = 2002;
years_and_events[1][1] = "Beauty Pageant";
years_and_events[1][2] = "Beauty pageant held globally";
years_and_events[2][0] = 2003;
years_and_events[2][1] = "Film Festival";
years_and_events[2][2] = "Film festival held globally";
years_and_events[3][0] = 2004;
years_and_events[3][1] = "Singing Contest";
years_and_events[3][2] = "Singing contest tournament held globally";
years_and_events[4][0] = 2005;
years_and_events[4][1] = "Wedding";
years_and_events[4][2] = "Wedding tournament held globally";
years_and_events[5][0] = 2007;
years_and_events[5][1] = "Karate Tournament";
years_and_events[5][2] = "Annual karate tournament held globally";
years_and_events[6][0] = 2008;
years_and_events[6][1] = "Beaty Pageant";
years_and_events[6][2] = "Beauty pageant held globally";
years_and_events[7][0] = 2009;
years_and_events[7][1] = "Film Festival";
years_and_events[7][2] = "Film festival held globally";
years_and_events[8][0] = 2010;
years_and_events[8][1] = "Singing Contest";
years_and_events[8][2] = "Singing contest tournament held globally";
years_and_events[9][0] = 2011;
years_and_events[9][1] = "Wedding";
years_and_events[9][2] = "Wedding tournament held globally";
var year = document.getElementById('year_list').value;
var event = document.getElementById('event_list').value;
var found = false;
for (var i = 0; i < years_and_events.length; i++) {
if ((year == years_and_events[i][0]) && (event == years_and_events[i][1])) {
document.getElementById('description').value = years_and_events[i][2];
document.getElementById('send_notice').style.visibility = "hidden";
document.getElementById('show_description').style.visibility = "visible";
found = true;
break;
}
}
if (found == false) {
document.getElementById('show_description').style.visibility = "hidden";
document.getElementById('send_notice').style.visibility = "visible";
}
}
答案 0 :(得分：2)
您需要为输入命名。所以：
<input name="description" />
答案 1 :(得分：1)
您需要设置<input type="hidden">的名称，如<input type="hidden" name="hiddenfield">
然后您可以通过$_GET['hiddenfield']在PHP中引用此字段。确保输入在表单中。
答案 2 :(得分：1)
您需要为输入指定名称，ID或两者：<input type="hidden" id="foo">
一些附注......
您可能想尝试一个非常有用的JavaScript库：
它包含大量的UI元素和插件，并且允许以比您当前编写的更简单的方式执行许多操作。
您可能还希望自己记录一下SQL注入，跨站点脚本和跨站点请求伪造。需要在代码中转义很多东西。
答案 3 :(得分：1)
在show_description div中，用$ description替换$ _GET ['description']。
编辑：我想我明白为什么你现在感到困惑。如果要在show_description div中显示描述输入的值，则需要使用javascript来执行此操作。 PHP是服务器端，当浏览器请求页面时，它只运行一次。如果您正在执行加载页面后发生的任何事情，则需要使用javascript。也就是说，对check_year_event（）函数进行此更改。 for (var i = 0; i < years_and_events.length; i++) {
if ((year == years_and_events[i][0]) && (event == years_and_events[i][1])) {
document.getElementById('description').value = years_and_events[i][2];
document.getElementById('show_description').innerHTML = years_and_events[i][2];
document.getElementById('send_notice').style.visibility = "hidden";
document.getElementById('show_description').style.visibility = "visible";
found = true;
break;
}
}
从index.php文件中删除echo $_GET['description']