Thanks to the work of Letmethink , we have some HTML5.
Saying this , there are plenty of differences between HTML5 and the targets.
Here are the one I've found. If you find some others, feel free to post !
W windows F Firefox
"clear image" doesn't work, this is due to shaders on openfl WF
"bezier curves" does a weird bezier curve polygon, instead of a stroke WF
"play sound" for sound effects don't always work. I've put a sound effect , when you click and it works like 8 on 10 times WF