How to run function on load?

How to run function on load?

  1. $('select[name="dropdown"]').on("change", function(){
  2.         if ( $(this).val() == "Hours" ) {

  3.             $("#something").show();

  4.         } else {
  5.             $("#something").hide();

  6.         }
  7.     });

How can I start this function automatically, without having to change dropdown select?

Thanks