php - isset($_POST ['x' ]) 仅在提交按钮名称为 ="submit"时有效

Question

我在使用回发时遇到问题，因为我有不止一种表单，而且 isset 仅适用于 name="submit" 按钮。

如果我使用 name="submit" 我的代码会正常工作，但如果我将名称更改为其他名称，isset($_POST['somethingelse'])永远都是假的，为什么会这样？

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 } ?>

例如这里，按预期工作(我可以保留值)作为 name="submit"并且 if (isset($_POST['submit'])) 在按钮提交时为真但如果我更改两个名称=""和 if (isset($_POST[''])) 然后它将不起作用，因为 isset 返回 false(即使按钮提交)。

Answer 1

这是正常的，因为只有点击的提交按钮被设置，而不是第二个，如果你点击名称为 submit 的提交按钮 isset($_POST['submit']) 会给你 true 和 isset($_POST['asdf']) false，如果你点击 asdf isset($_POST['submit']) 给出 false 和 isset($_POST['asdf']) true ，我对其进行了测试，它可以正常工作。

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>