CODEWITHSUNDEEP
php
Vanessa Roy
Vanessa Roy

Reputation: 23

Validation of a drop down list in PHP

I'm trying to validate a form in PHP. I have instructions not to change the form itself (The names of the fields for example) and in it there is a drop down list with this: <option value=""></option>

I tried to validate with this :

if (!isset($_POST['cboproduit'])){
$message.= "Vous devez sélectionner un téléphone <br />";}

but since there is a value with nothing in it, if I submit the form with the empty value it just saves an empty value.

How can I do this in a simple way?

Upvotes: 0

Views: 2683

Answers (4)

Rory
Rory

Reputation: 1

Just a thought but empty may not work for you because the value attribute of <option value=""></option> may be set to 0 for the first element (1 as the second and so on) and then this would mean that you could never delete the 0th element as empty checks for 0 and also for empty

if (empty($_POST['cboproduit'])){
    $message.= "Vous devez sélectionner un téléphone <br />";
 }

Upvotes: 0

Barmar
Barmar

Reputation: 781004

In addition to checking if the variable is set, you need to check if it's not empty:

if (!isset($_POST['cboproduit']) || $_POST['cboproduit'] === '') {
    $message .= "Vous devez sélectionner un téléphone <br />";
}

Upvotes: 2

Tomas Creemers
Tomas Creemers

Reputation: 2715

Different functions check different things about a variable. According to the documentation:

  • isset(): Determine if a variable is set and is not NULL.
  • empty(): A variable is considered empty if it does not exist or if its value equals FALSE.
  • array_key_exists(): returns TRUE if the given key is set in the array

So in your case, if (empty($_POST['cboproduit'])) seems the best way to proceed. It will detect if the value was somehow not transmitted (someone could edit the form in their browser before submitting it) or the empty option was selected.

(Note that this means that there is no way to determine the difference between a variable that does not exist and a variable that is null.)

Upvotes: 0

vee
vee

Reputation: 38645

You can use empty instead of isset as empty also checks if the variable exists or not:

 if (empty($_POST['cboproduit'])){
    $message.= "Vous devez sélectionner un téléphone <br />";
 }

Upvotes: 0

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