Detecting which form was submitted in php - php

Question

What would be a reliable way to detect which form was submitted in a situation like below? All submit to the same page, which in turn does things based on which form was submitted. Many drawbacks have been pointed out to the way this is being done. To top it all, even querystrings go to the same script. How would you suggest this be done?
Form one has two input fields, form two has three.
<?php
if ( isset($_POST['valOne']) && isset($_POST['valTwo']) && isset($_POST['valThree']) ) {
echo 'This is form three';
} elseif ( isset($_POST['valOne']) && isset($_POST['valTwo']) ) {
echo 'This is form two';
} else {
echo 'Neither one or two';
}
$formOne = '<form method="post" action="http://localhost/dev/form.php">';
$formOne .= 'Name: <input type="text" name="valOne" value="Foo" autocomplete="off"><br>';
$formOne .= 'Description: <input type="text" name="valTwo" value="Bar" autocomplete="off"><br>';
$formOne .= '<input type="hidden" name="secretVal" value="secretKey">';
$formOne .= '<input value="Add This" type="submit">';
$formOne .= '</form>';
$formTwo = '<form method="post" action="http://localhost/dev/form.php">';
$formTwo .= 'Name: <input type="text" name="valOne" value="Foo" autocomplete="off"><br>';
$formTwo .= 'Description: <input type="text" name="valTwo" value="Bar" autocomplete="off"><br>';
$formTwo .= 'URL: <input type="text" name="valThree" value="Tar" autocomplete="off"><br>';
$formTwo .= '<input type="hidden" name="secretVal" value="secretKey">';
$formTwo .= '<input value="Add This" type="submit">';
$formTwo .= '</form>';
$formThree = '<a href="http://localhost/dev/form.php?do=getIt">This is GET. Get it?<a/>';
echo $formOne;
echo '<br>';
echo $formTwo;
echo '<br>';
echo $formThree;
?>

Answer 1

You could use a hidden input with different names for the 2 forms and on server side you can check with if(isset($_POST['hidden_for_form1'])) or if(isset($_POST['hidden_for_form2'])).

Answer 2

You could add a form_id parameter to the form action.
<form method='post' action='http://localhost/dev/form.php?form_id=1'>
Then in your code switch on $_GET["form_id"];

Answer 3

I'd use hidden inputs
<input type="hidden" name="form" value="form1">
Also on a side note, is there any reason you're storing the form code in a variable?

Answer 4

Add a hidden input:
<input type="hidden" name="form" value="one">
<?switch($_POST['form']){
case "one":
...
?>
You can also assign the name and value to a submit button, but that doesn't work if the user presses enter

Answer 5

You need to assign some name in submit, like:
<input type="submit" name="form1" value="Add This">
<input type="submit" name="form2" value="Add This">
<input type="submit" name="form3" value="Add This">
so..
if(isset($_POST['form1'])){ //do some stuff }
if(isset($_POST['form2'])){ //do some stuff }
if(isset($_POST['form3'])){ //do some stuff }