PHP中的表单处理
[英]Form processing in PHP
问题描述
I have three questions about some code : 
关于某些代码，我有三个问题：
- How does
isset($_POST['submit'])knows when the submit button has been clicked.isset($_POST['submit'])知道何时单击了提交按钮。 I dont get the the mechanics behind this ?我不了解背后的机制吗？ - Why is each input element using a name with a value of
artist[]with the square brackets like that ?为什么每个输入元素都使用一个具有artist[]值且带有方括号的名称？ Are we defining and array inside HTML ?我们是在HTML中定义数组吗？ - I was told that the value of name given to an input element has to match the name given to the
$_POSTvariable.有人告诉我输入元素的名称值必须与$_POST变量的名称相匹配。 But in this case$_POSTis usingartistwith without the square brackets.但是在这种情况下， $_POST使用的artist没有方括号。 Whats going on here ?这里发生了什么 ？
. 。
<html>
<head></head>
<body>
<?php
// check for submit
if (!isset($_POST['submit'])) {
// and display form
?>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">
<input type="checkbox" name="artist[]" value="Bon Jovi">Bon Jovi
<input type="checkbox" name="artist[]" value="N'Sync">N'Sync
<input type="checkbox" name="artist" value="Boyzone">Boyzone
<input type="checkbox" name="artist" value="Britney Spears">Britney Spears
<input type="checkbox" name="artist" value="Jethro Tull">Jethro Tull
<input type="checkbox" name="artist" value="Crosby, Stills & Nash">Crosby, Stills & Nash
<input type="submit" name="submit" value="Select">
</form>
<?php
} else {
// or display the selected artists
// use a foreach loop to read and display array elements
if (is_array($_POST['artist'])) {
echo 'You selected: <br />';
foreach ($_POST['artist'] as $a) {
echo "<i>$a</i><br />";
}
} else {
echo 'Nothing selected';
}
}
?>
</body>
</html>
3 个解决方案
解决方案1
4 2013-10-02 15:11:57
1.How does isset($_POST['submit']) know when the submit button has been clicked.
Clicking the submit button causes the browser to submit the form (and include the name/value of the clicked submit button in the data). 单击提交按钮会使浏览器提交表单（并在数据中包含单击的提交按钮的名称/值）。
Submitting the form creates an HTTP request. 提交表单将创建一个HTTP请求。
The PHP won't run except as a reaction to the server receiving an HTTP request. 除了作为对服务器收到HTTP请求的响应之外，PHP不会运行。
The PHP examines the data to see if the submit buttons name/value in in it. PHP检查数据以查看其中是否包含提交按钮的名称/值。
- Why is each input element using a name with a value of "artist[]" with the square brackets like that?
Most form processing libraries will provide a way to access multiple elements with the same name as an array. 大多数表单处理库将提供一种访问与数组同名的多个元素的方法。 PHP's requires that the name ends in [] before allowing that. PHP要求名称必须以[]结尾，然后再允许。
I was told that the value of name given to an input element has to match the name given to the $_POST variable.
PHP's form data parser treats [] as a message to create an array and not as part of the name. PHP的表单数据解析器将[]视为创建数组的消息，而不是名称的一部分。 It is odd. 真奇怪
It does however, allow you to define such things as: 但是，它确实允许您定义以下内容：
<input type="checkbox" name="foo[bar][]" value="1">
<input type="checkbox" name="foo[bar][]" value="1">
<input type="checkbox" name="foo[bar][]" value="1">
<input type="checkbox" name="foo[oat][]" value="1">
<input type="checkbox" name="foo[oat][]" value="2">
<input type="checkbox" name="foo[oat][]" value="3">
And then loop over $_POST['foo'] to get an array of two items which can be looped over in turn. 然后循环$_POST['foo']以得到两个项目的数组，可以依次循环。
解决方案2
1 已采纳 2013-10-02 15:13:46
$_POST['submit']is set when the form is submitted and a input field with name "submit" exists.$_POST['submit']表单并且存在名称为“ submit”的输入字段时设置$_POST['submit']。 In your case, the<input type='submit'>has a name of "submit".在您的情况下， <input type='submit'>的名称为“ submit”。 (You can also get the value of the submit button using $_POST['submit'] which holds the value).（您也可以使用保存值的$ _POST ['submit']获取提交按钮的值）。 The names have artist[] because it declares an array to be passed as the form is processed.
名称具有artist []，因为它声明了在处理表单时要传递的数组。 You can use it to group values together. 您可以使用它来将值分组在一起。 Usually, it's done by artist[name],artist[album]etc. which can the be referenced in PHP using_POST['artist']['name'].通常，它是由artist[name]，artist[album]等完成的，可以在PHP中使用_POST['artist']['name']进行引用。Sort of follows from 2. Using empty square brackets makes an array without associations.
从2开始进行排序。使用空方括号会使数组不相关。 You'd reference the first field as $_POST['artist'][0]and next$_POST['artist'][1].您将第一个字段引用为$_POST['artist'][0]，下一个$_POST['artist'][1]。
When all fields have been given the same name, an array is built and you can reference it in PHP like 3. 给所有字段指定相同的名称后，将构建一个数组，您可以像3一样在PHP中引用它。
解决方案3
0 2013-10-02 15:15:12
The submit button actually submits the form and it's a POST value on it's own.
提交按钮实际上是提交表单，它本身就是一个POST值。 So if it's set it means that the form was submitted. 因此，如果已设置，则表示表单已提交。 Though, it would be better to check if $_SERVER['REQUEST_METHOD']is equal to 'POST'.不过，最好检查$_SERVER['REQUEST_METHOD']是否等于'POST'。Yes, it's defining an "array", but it's wrong because in the last 4 checkboxes it doesn't have the square brackets.
是的，它定义了一个“数组”，但这是错误的，因为在最后四个复选框中没有方括号。 $_POST['artist']would contain an array with all the checkboxes values (true or false, depending on wheteher they were checked or not respectively).$_POST['artist']将包含一个带有所有复选框值的数组（是或否，取决于是否分别选中它们）。
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.