What is the best way of checking whether or not a form has been submitted to determine whether I should pass the form's variables to my validation class?

First I thought maybe:


But that will always return true as a superglobal is defined everywhere. I don't want to have to iterate through each element of my form with:

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

Whilst writing this question I thought of a much more basic solution, add a hidden field to act as a flag that I can check.

Is there a 'cleaner' way to do it than adding my own flag?

Solution 1

For general check if there was a POST action use:

if ($_POST)

EDIT: As stated in the comments, this method won't work for in some cases (e.g. with check boxes and button without a name). You really should use:


Solution 2

How about


Solution 3

Actually, the submit button already performs this function.

Try in the FORM:

<form method="post">
<input type="submit" name="treasure" value="go!">

Then in the PHP handler:

if (isset($_POST['treasure'])){
echo "treasure will be set if the form has been submitted (to TRUE, I believe)";

Solution 4


if(isset($_POST['submit'])) // name of your submit button

Solution 5


Solution 6

Try this

 <form action="" method="POST" id="formaddtask">
      Add Task: <input type="text"name="newtaskname" />
      <input type="submit" value="Submit"/>

    //Check if the form is submitted
    if($_SERVER['REQUEST_METHOD'] == 'POST' && !empty($_POST['newtaskname'])){


Solution 7

On a different note, it is also always a good practice to add a token to your form and verify it to check if the data was not sent from outside. Here are the steps:

  1. Generate a unique token (you can use hash) Ex:

    $token = hash (string $algo , string $data [, bool $raw_output = FALSE ] );
  2. Assign this token to a session variable. Ex:

    $_SESSION['form_token'] = $token;
  3. Add a hidden input to submit the token. Ex:

    input type="hidden" name="token" value="{$token}"
  4. then as part of your validation, check if the submitted token matches the session var.

    Ex: if ( $_POST['token'] === $_SESSION['form_token'] ) ....

Solution 8

I had the same problem - also make sure you add name="" in the input button. Well, that fix worked for me.

if($_SERVER['REQUEST_METHOD'] == 'POST' && !empty($_POST['add'])){
    echo "stuff is happening now";

<input type="submit" name="add" value="Submit">

Solution 9

You could also use: