The IDL file has crossorigin but the specs say crossOrigin. Easy to fix, but I don't know how many sites we are going to break...
We do spell it crossOrigin in HTMLImageElement (as do other browsers)... Other browsers do not appear to have it on HTMLMediaElement yet so I think it should be relatively safe to rename.
Created attachment 720680 [details] [diff] [review] patch
Comment on attachment 720680 [details] [diff] [review] patch r=me As Anne said, the number of sites using this is almost certainly 0.
I've added this bug to the compatibility doc. Please correct the info if wrong. https://developer.mozilla.org/en-US/docs/Site_Compatibility_for_Firefox_22
https://developer.mozilla.org/en-US/docs/DOM/HTMLMediaElement looks up-to-date.