Why use percentage value for div's width in CSS?

Question

I am reading articles about css. I found out that many of writers suggest to use % value for div\'s width or height.

I am using pixels all the time.

Why should I

Answer 1

All in all, if you use images on your site, using percent for main contianer may not be the best approach. In that case, you'd want to use pixels.

Advice: Use Pixels for main contianer and percent for content.