querySelector vs getElementById

Get Element By Id

• It returns a node list which is live, meaning if you add or remove any element from the DOM the node list will update
• It is faster relative to the query selector methods

Query Selector

• It returns a node list which was available at the time of the execution

Also Read:

1. A simple requestAnimationFrame example visually explained
2. position:fixed
3. Applying floats and clearfix to block elements
4. position: relative
5. Promise javascript examples