I need a little help. I'm playing a video with the html tag :
<video id = "video" src = "url"> </video>

I would like to recover the value of the mediaId variable which is returned by webos but I don't know how to do it at all.
Here is what I tried:

var vid = document.getElementById("video");
if (vid.mediaId == "") {
console.log("mediaId is null");
Thank you.