VideoJS is a HTML5 Video Player, recently i started using it in a project i choose it for is supper easy installation which is easy by just adding one video.js file and video-js.css a css file, both are hosted on free CDN. While working on the project i find out that it does not fall back on it own when using an flv or MP4 source file in Firefox web browser, i googled a bit and found out that Firefox can not play MP4 files, to make consistent in all browser i have to force video.js to play in flash to make this this work you have to do the following in your embed code.