814923 - implement CSS.supports

Status: RESOLVED DUPLICATE of bug 779917

(Core :: DOM: CSS Object Model, defect)

Comment 1

[Cameron McCormack (:heycam)]

Attachment: patch

I wasn't totally sure what to do if a premature end of the string was reached within a condition or property value.  The behaviour that fell out was the same as EOF handling in style sheets.  For example these return true:

  CSS.supports("(color: green) /*")
  CSS.supports("(color: green")
  CSS.supports("(font-family: 'Helvetica")
  CSS.supports("color", "green /*")
  CSS.supports("font-family", "'Helvetica")

and these false:

  CSS.supports("(font-family: 'Helvetica\n")
  CSS.supports("font-family", "'Helvetica\n")

Another I was unsure about was:

  CSS.supports("Color", "green")

That is currently returning true, but the spec says it should return true only if it is "a literal match for the name of a CSS property that the UA supports".

Comment 2

[Cameron McCormack (:heycam)]

This really should have been on bug 779917; moving the patch there now.