To start a video automatically use the autoplay attribute:
<video width="320" height="240" autoplay>
<source src="movie.mp4" type="video/mp4">
<source src="movie.ogg" type="video/ogg">
Your browser does not support the video tag.
</video>
HTML Video - Browser Support
Currently, there are 3 supported video formats for the &amp;lt;video&amp;gt; element: MP4, WebM, and Ogg:
Browser MP4 WebM Ogg
Internet Explorer YES NO NO
Chrome YES YES YES
Firefox YES YES YES
Safari YES NO NO
Opera YES (from Opera 25) YES YES