Does the JavaScript onclick event not work on <select> 's?

Question

For some reason the code below it is not working correctly. Unless I\'m being quite stupid with my JavaScript I can\'t see what\'s going wrong besides the onclick events not

Answer 1

DEMO

var dropdown = document.getElementById('drop_down');

dropdown.onchange = function() {
  var selected = dropdown.options[dropdown.selectedIndex].value;

  switch(selected) {
    case 'other':
      document.getElementById('other').value = "";
      document.getElementById('other').style.display = 'block'; 
      document.getElementById('otherBR').style.display = 'block';
      break;
    default:
      document.getElementById('other').style.display = 'none'; 
      document.getElementById('otherBR').style.display = 'none';
      break;
  }
}