Mozilla has become the latest browser maker to start phasing out support for Flash. It will start blocking some elements next month before a total block next year.

The developer says it has already tweaked Firefox to reduce the reliance on plugins for features such as video streaming and microphone access. But it says its expanding that program because having stability and usability failures in order to get enhanced Web experiences is no longer “a trade-off users should have to accept.”

The gradual program will start next month when Firefox will block a specific list of Flash content types that it says are invisible to users. The list will only include content where there’s a specific HTML alternative available to developers and the list will be expanded over time.

The next step will come later this year when Mozilla will block any Flash that is used “to check content viewability” which is something that’s mainly used for what have been dubbed supercookies. Again, the change will come only as and when an equivalent HTML API is available.

The gradual approach won’t last forever. At some point in 2017 (on what should perhaps be called F Day) Mozilla will introduce a blanket rule that any Flash plugin is blocked by default and can only be run after a user clicks to activate it. Mozilla is strongly suggesting developers switch to HTML alternatives before that policy takes effect.