HTML class attribute with spaces, it is a W3C valid class?

Question

About HTML class attribute, that assigns CSS class (or classes?) to a tag. The use of spaces, like in

....
         


        

Answer 1

This is supported in IE 7 and up, including all modern, non-IE browsers. As other commenters have pointed out, it is actually a list of classes, not a single class with spaces.

A better way to understand this is to give your example a few more options:

....
....
....

.a.b {} in your css will target the first tag.
.a {} will target the first and second tags.
.b {} will target the first and third tags.

This is why using multiple classes on a single element can be very helpful.

For questions of CSS selectors and pseudo selectors, I like to use this (slightly outdated) table http://kimblim.dk/css-tests/selectors/