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

I, personally, dislike websites which have a % width for the main content area because of the inconsistency. It's best to use a pixel width of about 1000 pixels, maybe a bit less, for the whole website so that it will work for all resolutions.

As for elements inside the main content area, I tend to use percent widths because I don't really want to both with calculating the exact pixel values. The result is set in stone anyway because the thing that it's a percentage of is constant, as opposed to the monitor's resolution, which varies between users.

To sum it up: only use percentages when every user is going to get the same result because of a parent element having a fixed (pixel) width. Otherwise there will be inconsistencies in your design, making it so that you can't use any flashy images and the website may look ugly to users with giant / tiny monitors. If you are going to use percentage widths you simply have to test the website with different resolutions!