Created attachment 707183 [details] [diff] [review]
shows that IE/Chrome/Opera don't support it.
Comment on attachment 707183 [details] [diff] [review]
r=dbaron. If you land after bug 835169, please remove the outer if, though.
Will do. Thanks.
As it wasn't documented elsewhere, and it was non-standard and quite cryptic, I don't think we need more doc. Switch back to dev-doc-needed if you disagree.