Firefox 4 to Add CSS3 calc()

Firefox 4 to Add CSS3 calc():

Paul Rouget, Mozilla:

This feature hasn't landed yet in any Firefox tree but work to implement it is underway.

Firefox will support the CSS calc() value, which lets you compute a length value using an arithmetic expression. This means you can use it to define the sizes of divs, the values of margins, the widths of borders, and so forth.

Ace.