isset param null php code example

Example 1: isset in php

$age = 0;
// Evaluates as true because $age is set
if (isset($age)) {
echo '$age is set even though it is empty';
}

Example 2: what is isset in php

The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL.

This function returns true if the variable exists and is not NULL, otherwise it returns false.