Does anyone have stats on how fast Firefox users upgrade to the latest version? I've updated the codepen I linked to earlier and it now works correctly in IE8+, Chrome, and will work in Firefox 48 (the next version, released August 2nd) once
https://bugzilla.mozilla.org/show_bug.cgi?id=962251 (focus/blur events not showing relatedTarget attribute) is fixed. I know this code won't make it up before then, but I don't know how comfortable I feel knowing the tabbing isn't working properly for some users.