Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

CSS CSS Layout Techniques Grid Layout Creating the Grid Container

Na Da
Na Da
5,041 Points
Posted by Na Da
Na Da
5,041 Points

Are child selectors expensive?

Just wanted to know the best practices involving child selectors.

1 Answer

Jacob Moyle
Jacob Moyle
6,150 Points

Hello Naomi,

Short answer: They're in the middle.

"Selectors have an inherent efficiency, and to quote Steve Souders, the order of more to less efficient CSS selectors goes thus:

  1. ID, e.g. #header
  2. Class, e.g. .promo
  3. Type, e.g. div
  4. Adjacent sibling, e.g. h2 + p
  5. Child, e.g. li > ul
  6. Descendant, e.g. ul a
  7. Universal, i.e. *
  8. Attribute, e.g. [type="text"]
  9. Pseudo-classes/-elements, e.g. a:hover

Quoted from Even Faster Websites by Steve Souders"

If you are looking for a more in depth article, I would recommend this one (which is where I pulled that block of text from). I hope this is helpful!