# Help with understanding HTML5/JavaScript mp3 jukebox

**URL:** https://forum.kirupa.com/t/help-with-understanding-html5-javascript-mp3-jukebox/633396
**Category:** programming
**Created:** [June 26, 2015, 1:44am UTC](https://forum.kirupa.com/t/help-with-understanding-html5-javascript-mp3-jukebox/633396 "2015-06-26T01:44:24Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![codypersinger](https://avatars.discourse-cdn.com/v4/letter/c/779978/32.png) [@codypersinger](https://forum.kirupa.com/u/codypersinger)
#### Post date: [June 26, 2015, 1:44am UTC](https://forum.kirupa.com/t/help-with-understanding-html5-javascript-mp3-jukebox/633396/1 "2015-06-26T01:44:24Z")

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I’m working on a personal project for my portfolio, and I’m trying to emulate the functionality of this site: [http://thisweeksplaylist.co](http://thisweeksplaylist.co)[1] . I couldn’t understand their minified `footer.js` file, which seems to be the music player (they also have a `header.js`, not sure if it’s part of what I’m missing). I’m having a hard time finding a tutorial anywhere that covers all the functionality their music player has.

I’m also confused by their HTML markup. I don’t understand how the JavaScript is interpreting the `<li audio="">` elements.

Particular functionality I want to include but am unsure about is making each `<li>`'s background a song progress trackbar. It was easy enough to make an array in JS that handles normal `<audio src=""`\> elements, but the particular combination of functionality and markup that is used here has me baffled.