disableExternalCapture methods on the
window object have been removed. They were non-standard Netscape-derived APIs deprecated since Firefox 3 and the implementation has been no-op (doing nothing). Meanwhile,
releaseEvents are kept for backward compatibility as Google’s research revealed that many sites relied on those methods for feature detection.
preventCapture methods, which were in the earlier W3C draft, have also been removed. The
stopPropagation method can be used instead.
Additionally, the non-standard
getPreventDefault method, deprecated since Firefox 16, will be removed soon in favour of the
defaultPrevented property. If
getPreventDefault is used in a Web page, Web Console shows a warning about the deprecation.