====== onSources() ======
wrtc.onSources() is called when [[ixnx:wrtc:js:api:sources_array|list of available local audio and video sources]] has been populated.

<WRAP center round important 100%>
wrtc.onSources() occur only in Chrome and Safari browsers. If other browser is used wrtc.onSources() never occur.
</WRAP>

You can use this event function to call [[ixnx:wrtc:js:api:wrtc:get|wrtc.get("audioSources")]] and [[ixnx:wrtc:js:api:wrtc:get|wrtc.get("videoSources")]] and allow user select which camera and microphone to use.

===== Occurs =====
List of audio and video sources has been populated.

As the Chrome browser takes a while to populate the sources lists they cannot be accessed right away after page has been loaded. Do not attempt to [[ixnx:wrtc:js:api:wrtc:get|wrtc.get()]] the lists in [[ixnx:wrtc:js:api:wrtc:init|wrtc.init()]]. Once Chrome has finished preparing the lists wrtc.onSources() will occur indicating you are welcome to access the lists using [[ixnx:wrtc:js:api:wrtc:get|wrtc.get()]]

===== Arguments =====
wrtc.onSources()
  * None

===== Example =====
Fill <select> dropdown asource with entries from audio_sources:
  wrtc.onSources() {
      var audio_sources = wrtc.get("audioSources");
      for (var i = 0; i < audio_sources.length; i++) {
        var option = document.createElement("option");
        option.text = audio_sources[i].label || 'microphone ' + (i + 1);
        option.value = audio_sources[i].id;
        document.getElementById('asource').add(option);
      }
        -- same for video --
  }
  ...
  <select id="asource">
    <option value=0 selected>default</option>
  </select>
User can later select microphone from list of available ones in dropdown asource, set [[ixnx:wrtc:js:api:wrtc:audiosource|wrtc.audioSource]] to selected dropdown value and call [[ixnx:wrtc:js:api:wrtc:changemedia|wrtc.changeMedia()]]. And the same for video.

===== See Also =====
[[ixnx:wrtc:js:api:wrtc:get|wrtc.get("audioSources")]], [[ixnx:wrtc:js:api:wrtc:get|wrtc.get("audioDestinations")]] and [[ixnx:wrtc:js:api:wrtc:get|wrtc.get("videoSources")]]

[[ixnx:wrtc:js:api:wrtc:audiosource|wrtc.audioSource]], [[ixnx:wrtc:js:api:wrtc:audiodestination|wrtc.audioDestination]] and [[ixnx:wrtc:js:api:wrtc:videosource|wrtc.videoSource]]