isset（$\u POST['x']）仅在“提交”按钮name=“提交”时有效

Question

我在使用回发时遇到问题，因为我有多个表单，isset只能使用name=“submit”按钮。

如果我使用name=“submit”我的代码可以正常工作，但是如果我将名称更改为其他名称，isset（$\u POST['somethingelse']）将始终为false，为什么会发生这种情况？

编辑：

<input type="submit" name="submit" value="Submit" onclick ="validate(document.getElementById('form')); return false;" />

if (isset($_POST['submit'])) <-- works as expected



<input type="submit" name="asdf" value="Submit" onclick ="validate(document.getElementById('form')); return false;" />


if (isset($_POST['asdf'])) <-- does not works as expected

编辑2：

<?php
$validated = false;
if (isset($_POST['submit'])) {
    // preserve form values by storing the values from $_POST into variables
    $test = $_POST['test'];
    // validated is now true as submit button only submits if validated (script)
    $validated = true;
} else {
    // make variables empty as there's no values to preserve
        $test = '';
}

if (!$validated) {
?>
<form id="form" action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
<p>Test: <input type="text" name="test" size="20" value="<?php echo $test ?>" /></p>
<p><input type="submit" name="submit" value="Submit" onclick ="validate(); return false;" /></p>
<?php } ?>

例如，此处，按预期工作（我可以保留值）为name=“submit”，如果按钮提交时（isset（$\u POST['submit']）为true，但如果我同时更改name=”“和if（isset（$\u POST[']），则它将不工作，因为isset返回false（即使按钮提交）。

Answer 1

这是正常的，因为只有单击的提交按钮被设置，而不是第二个，如果您单击名为submitisset（$\u POST['submit']）的提交按钮，则会给出true和isset（$\u POST['asdf']）false，如果您单击asdfisset（$\u POST['submit']）会给出false和isset（$\u POST['asdf']）true，我测试了它，它的工作没有任何问题。

测试代码：

<?php
$validated = false;
if (isset($_POST['submit'])) {
    // preserve form values by storing the values from $_POST into variables
    $test = "submit";
    // validated is now true as submit button only submits if validated (script)
    $validated = true;
} 
else if(isset($_POST['asdf'])){
        $test = "asdf";
    // validated is now true as submit button only submits if validated (script)
    $validated = true;
}
else {
    // make variables empty as there's no values to preserve
        $test = '';
}
if (!$validated) {
echo $test;
} ?>
<form id="form" action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
<p>Test: <input type="text" name="test" size="20" value="<?php echo $test ?>" /></p>
<p><input type="submit" name="submit" value="Submit" onclick ="validate(); return false;" /></p>
<p><input type="submit" name="asdf" value="Submit" onclick ="validate(document.getElementById('form')); return false;" />
</p>