title: Differences between timeline code vs Document class code
body: <p>I'm trying to explain the differences between writing timeline code vs Document Class code, so far I have:</p>
  
  <pre><code>Timeline code:
  - doesn't require a package and class declaration
  
  Document Class code:
  - requires a package and class declaration
  
  Timeline code:
  - starts working on the top-most line
  
  Document Class Code:
  - starts working from the constructor function
  
  Timeline code:
  - loops, conditionals and event listeners can be **outside** of a function
  
  Document Class Code:
  - loops, conditionals and event listeners must be **inside** a function
  </code></pre>
  
  <p>Are these correct, and is there anything else that would trip up people who are making the transition?</p>