interview.js

el.addEventListener('click', function (e) {
    e.target.style.display = 'none';
});

// Instead of using jQuery's $('selector') for grabbing an element, just use these
var elem = document.querySelector('selector'); // Returns a DOM Node
var elems = document.querySelectorAll('selector'); // Returns a nodelist

// Then for event listeners it's just:
elem.addEventListener('click', function (e) {
  // e is the event,
  var event = e,
      // e.target will give you what's been clicked
      target = e.target;
      
  // You can change styles by accessing the style property
  target.style.display = 'none';
  
  // Add a class
  target.classList.add('className');
  
  // Remove a class
  target.classList.remove('className');
  
  // Remove element
  target.parentNode.removeChild(target);
});

// For anything else, just use: http://youmightnotneedjquery.com/