Max-width vs. width of an element

This div element has a max-width of 500px

This div element has a width of 500px.

Resize the browser window to smaller than 500 px wide to see the effect!

Using both max-width and width

This div element has a width of 100% and a max-width of 900px.

Resize the browser window to larger than 900 px wide to see the effect!