Comments

Which describe what happens and why. 

// This comment occupies a line of its own
alert('Hello');
alert('World'); // This comment follows the statement
/* An example with two messages.
This is a multiline comment.
*/
alert('Hello');
alert('World');

Can be put into any place of the script. They don't affect the execution because the engine simply ignores them.

Comments — Structure map

Clickable & Draggable!

Comments — Related pages:

DOM tree

JSON methods, toJSON

Promises chaining

Node properties: type, tag and contents

Comments

Functions