CODEWITHSUNDEEP
phppostif-statementisset
zeckdude
zeckdude

Reputation: 16163

Why do I need the isset() function in php?

I am trying to understand the difference between this:

if (isset($_POST['Submit'])) { 
  //do something
}

and

if ($_POST['Submit']) { 
  //do something
}

It seems to me that if the $_POST['Submit'] variable is true, then it is set. Why would I need the isset() function in this case?

Upvotes: 13

Views: 16740

Answers (6)

jamal
jamal

Reputation: 1

if user do not enter a value so $_post[] return NULL that we say in the description of isset:"

isset will return TRUE if it exists and is not NULL otherwise it is FALSE.,but in here isset return the true "

Upvotes: 0

alex
alex

Reputation: 490233

In your 2nd example, PHP will issue a notice (on E_NOTICE or stricter) if that key is not set for $_POST.

Also see this question on Stack Overflow.

Upvotes: 1

Gaurav Sharma
Gaurav Sharma

Reputation: 2848

The code


if($_POST['Submit'])
{
//some code
}

will not work in WAMP (works on xampp)
on WAMP you will have to use


if (isset($_POST['Submit'])) { 
  //do something
}

try it. :)

Upvotes: 0

KJ Saxena
KJ Saxena

Reputation: 21838

You basically want to check if the $_POST[] variable has been submitted at all, regardless of value. If you do not use isset(), certain submissions like submit=0 will fail.

Upvotes: 3

Kevin
Kevin

Reputation: 13226

isset will return TRUE if it exists and is not NULL otherwise it is FALSE.

Upvotes: 4

kennytm
kennytm

Reputation: 523274

Because

$a = array("x" => "0");

if ($a["x"])
  echo "This branch is not executed";

if (isset($a["x"]))
  echo "But this will";

(See also http://hk.php.net/manual/en/function.isset.php and http://hk.php.net/manual/en/language.types.boolean.php#language.types.boolean.casting)

Upvotes: 20

Related Questions