how do i add a class to my h1 with javascript?

I'd like to have JavaScript add a class to my h1 elements automatically.

How would I add JavaScript to replace the h1 element with h1="classs" etc?

Answer

Using Jquery it's simple. Loop all of the h1 elements adding the classname to it

$(function(){
  $('h1').each(function(){
    $(this).addClass('classname');
  });
});

Or if you want to add a class per specific element ID

  $(function(){
    $('#eleID').addClass('classname');
  });