Added article for HTML5 Audio (freeCodeCamp#1344)

src/pages/html/html5-audio/index.md

@@ -7,7 +7,19 @@ This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/
 
 <a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
 
-<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->
+The HTML <audio> element is used to embed sound content in documents. It may contain one or more audio sources, represented using the src attribute or the [source](<source>) element
+```
+<audio controls>
+  <source src="tutorial.ogg" type="audio/ogg">
+  <source src="tutorial.mp3" type="audio/mpeg">
+Your browser does not support the audio element.
+</audio>
+```
+The controls attribute adds audio controls, like play, pause, and volume.
+
+The [source](<source>) element allows you to specify alternative audio files which the browser may choose from. The browser will use the first recognized format.
+
+The text between the [audio](<audio>) and [audio](</audio>) tags will only be displayed in browsers that do not support the <audio> element.
 
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