The bdi element represents a span of text that is to be isolated from its surroundings for the purposes of bidirectional text formatting.
Browser support: Firefox, Chromium, Safari
See also the comments about bidi isolation in general at https://wpdev.uservoice.com/forums/257854-microsoft-edge-developer/suggestions/10784463-support-dir-auto
Beni Cherniavsky-Paskin commented
HTML5 also redefines that any element with `dir` attribute (whether ltr / rtl / auto) should be bidi-isolated.
Comprehensive doc: http://www.w3.org/International/articles/inline-bidi-markup/#dirattribute
Browser support: Firefox, Chromium, Safari, Opera
It should also be possible to explicitly control with `unicode-bidi: isolate` CSS
Browser support [prefixed]: Firefox, Chromium, Safari, Opera.)
If you have any backwards-compatibility doubts about redefining behaviour of the `dir` attribute,
please at least support `unicode-bidi: isolate`. Then authors can opt in to the new `bdi` and `dir` behavior with short CSS: http://www.w3.org/International/articles/inline-bidi-markup/#cssshim