<button onclick="getFirstBuffRange()" type="button">Get first buffered range</button> <br> <video id="video1" controls="controls"> <source src="/statics/demosource/mov_bbb.mp4" type="video/mp4"> <source src="/statics/demosource/mov_bbb.ogg" type="video/ogg"> Your browser does not support HTML5 video. </video> <script> myVid=document.getElementById("video1"); function getFirstBuffRange() { alert("Start: " + myVid.buffered.start(0) + " End: " + myVid.buffered.end(0)); } </script> <p>Video courtesy of <a href="http://www.bigbuckbunny.org/" target="_blank">Big Buck Bunny</a>.</p>