isset()

Determines if a variable is declared, is not NULL, and checks multiple variables at once.

Syntax

php

isset(mixed $var, mixed ...$vars): bool

Example

php

$name = "Alice";
if (isset($name)) { echo "name is set"; }

if (isset($_POST["email"], $_POST["password"])) {
  // both values are present
}

unset($name);
var_dump(isset($name)); // bool(false)