Add another class to a div

Question

I have a function that checks the age of a form submission and then returns new content in a div depending on their age. Right now I am just using getElementById to replace

Answer 1

If the element has no class, give it one. Otherwise, append a space followed by the new className:

  var el = document.getElementById('hello');
  if(el) {
    el.className += el.className ? ' someClass' : 'someClass';
  }