Why use ISSET()?

[chinmay.sahoo]

The isset () function is used to check whether a variable is set or not. If a variable is already unset with unset() function, it will no longer be set. The isset() function return false if testing variable contains a NULL value


Syntax: isset(variable1, variable2......)


Eg:

<?php
$var1 = 'test';
var_dump(isset($var1));
?>