Google announced that it is now defaulting to the HTML5 player on the web for YouTube embeds, moving to iframes. Along with this, they’re deprecating the “old style” of Flash <object> embeds and their Flash API.
The company is encouraging all embeddes to use the iframe API, which as it notes, can inelligently use whichever technology the client supports. Google says in a blog post:
Four years ago, we wrote about YouTube’s early support for the HTML5 ...
February 4, 2015