How Can I Reliably Check for Form Submission in PHP?

Checking Form Submission in PHP

To determine if a form has been submitted and thus should be validated, different approaches can be employed.

Initially considered was checking the existence of the $_POST superglobal:

isset($_POST)

However, this approach always returns true because superglobals are globally defined. Iterating through each form element is also not ideal:

if(isset($_POST['element1']) || isset($_POST['element2']) || isset(...etc)

A simpler solution involves adding a hidden flag field to check:

<!-- Form code here -->
<input type="hidden" name="submitted" value="1">

// Check if the "submitted" field is set
if (isset($_POST['submitted'])) {
    // Form has been submitted, validate input
}

Cleaner Alternative

A more comprehensive approach involves checking the request method:

if ($_SERVER['REQUEST_METHOD'] == 'POST')

This method is preferable because it also works in cases where checkboxes or buttons without names might not be present in the $_POST superglobal.

Note: It's important to consider potential edge cases where the request method may not be set to 'POST,' such as when the form is submitted without JavaScript.

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