Iâ€™ve just read last week that Firefox would implement calc() in their new version of Firefox. Itâ€™s not out in any publicly released version yet but it is coming as they talked about it on their developers blog.
Why should you care?
Ever had an element that needed to have a percentage width with padding? Up until now, because of the way the box model works in
modern browsers, you had to wrap the content in a container to which youâ€™d apply the padding. Thatâ€™s because when you define padding to an element the value is added to the width, which is the proper way of doing it.