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    Register callback event
    • 18 Jan 2024
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    Register callback event

    • Updated on 18 Jan 2024
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    Article summary

    JavaScript API - Supported Events

    You can register callback events for a variety of events, including HTML5 media events and Moving Image-specific events. This allows you to trigger actions in your JavaScript code when these events occur.

    Registering and unregistering callback events

    To register a callback event, use the Player.registerEventListener() function. This function takes three arguments:

    • eventName: The name of the event.

    • callback: A function to be called when the event is triggered.

    • priority (optional): An integer value that determines the order in which callback functions are called. Higher priorities are called first.

    To unregister a callback event, use the Player.unregisterEventListener() function. This function takes two arguments:

    • eventName: The name of the event.

    • callback: The function to be unregistered.

    Supported events

    The following events are supported:

    • All known HTML5 media events (see Media Events: https://www.eventbrite.com/d/pa--media/events/ for a list).

    • Moving Image-specific events:

      • chapterclicked: Triggered when the user clicks on a chapter.

      • lightadstarted: Triggered when a light ad begins playing.

    Example

    The following example shows how to register callback events for the playing and pause events:

    HTML

    <div id="player_container"></div>
<div id="while_playing" style="display: none">video is playing!</div>

    JavaScript

    function playingCallback(event) {
  var whilePlaying = document.getElementById('while_playing');
  whilePlaying.style.display = "block";
}

function pauseCallback(event) {
  var whilePlaying = document.getElementById('while_playing');
  whilePlaying.style.display = "none";
}

// Create a new player instance.
function createPlayer() {
  var initPlayer = {
    success: function(playerApi) {
      playerApi.registerEventListener('playing', playingCallback);
      playerApi.registerEventListener('pause', pauseCallback);
    },
    parameters: {
      configType: 'vmpro',
      playerId: '<PlayerID>',
      videoId: '<VideoID>',
      apiUrl: '//d.video-cdn.net/play',
      flashPath: '//e.video-cdn.net/v2/'
    }
  };

  VideoPlayer.Collection.addPlayerById('player_container', initPlayer);
}

// Add the player.
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = '//e.video-cdn.net/v2/embed.js';
head.appendChild(script);

script.onload = (function() {
  createPlayer();
});

    When the video starts playing, the playingCallback() function will be called and the while_playing element will be displayed. When the video is paused, the pauseCallback() function will be called and the while_playing element will be hidden.

    Optimization suggestions

    • The example code above can be optimized by moving the createPlayer() function to the bottom of the <body> element. This will ensure that the player is not created until the DOM is fully loaded.

    • The script.onload event handler can be simplified using an arrow function:

    JavaScript

    script.onload = () => createPlayer();

    • The while_playing element can be hidden by default by adding the following CSS rule:

    CSS

    #while_playing {
  display: none;
}

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