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

Question

I am trying to understand the difference between this:

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

and

if ($_POST[         


        

Answer 1

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. :)