how can i print value out of if condition when i get value from isset post?

PHP now i'm trying to echo tha variable value out of if and isset area.

if(isset($_POST['submit'])){
  $today_date = date("Y-m-d");
  $id_user = $_POST['id_user'];
  $fullName_user = $_POST['fullName_user'];
}
echo $today_date;

//how can i print out of if condition.