01-17-2016 , 10:56 PM
Quote:Mozilla has added a feature to Firefox 46 that will convert old YouTube Flash code to HTML5 Video automatically under certain circumstances.
When YouTube started out, Flash was the dominating technology used to stream video on the Internet, and the first player that YouTube made available to webmasters to embed videos on third-party sites used Flash exclusively.
YouTube changed the code later on to reflect changes in streaming technologies. From a technical perspective, YouTube started to offer embed codes as iframes instead of objects.
The Flash code works fine after all these years, but only if Adobe Flash is installed in the browser. If that is not the case, a "plugin is missing" error message is displayed.
If you take this old Ghacks article on Line Rider, and there specifically the first video embedded on the page, you will get the error message "A plugin is needed to display this content" if Flash is not installed in the browser or blocked on the site.
read article HERE