SoundManager 2: Lazy Loading Example

This is an example of dynamically loading SoundManager 2 using JS, after window.onload() has fired.

How it works

This page waits until window.onload(), delays 1 second and loads soundmanager2.js, which should then start up.

SoundManager 2 status: Waiting for window.onload()...

 * Dynamic script loading helper
 * Normalizes good browser onload() vs. IE readyState weirdness

function loadScript(sURL, onLoad) {

  function loadScriptHandler() {
    var rs = this.readyState;
    if (rs == 'loaded' || rs == 'complete') {
      this.onreadystatechange = null;
      this.onload = null;
      if (onLoad) {

  function scriptOnload() {
    this.onreadystatechange = null;
    this.onload = null;

  var oS = document.createElement('script');
  oS.type = 'text/javascript';
  if (onLoad) {
    oS.onreadystatechange = loadScriptHandler;
    oS.onload = scriptOnload;
  oS.src = sURL;


// Wait for window load, then load soundmanager2.js, let it start and play a test sound

window.onload = function() {

  msg('Window loaded, waiting 1 second...');

  setTimeout(function() {

    msg('Loading soundmanager2.js...');

    loadScript('../../script/soundmanager2.js', function() {

      // SM2 script has loaded

      soundManager.url = '../../swf/';

      soundManager.onready(function() {
        msg('started OK');

      soundManager.ontimeout(function() {
        msg('Loaded OK, but unable to start: unsupported/flash blocked, etc.');

      soundManager.beginDelayedInit(); // ensure start-up in case document.readyState and/or DOMContentLoaded are unavailable




Handling flash blockers

It's good to let users see the flash component of SM2, so those with flash blockers can unblock it and allow SM2 to start. For more info on this, see the Flashblock example.

Making SM2 wait for window.onload()

If you prefer to have the library wait for window.onload() before calling soundManager.onload()/onerror() methods, you can modify SM2's "waitForWindowLoad" property:

soundManager.waitForWindowLoad = true;

Preventing auto-init using SM2_DEFER

If you want to completely defer the normal start-up of SM2 and call the SoundManager() constructor yourself, you can declare an SM2_DEFER global and set it to true.

window.SM2_DEFER = true;
// some time later, manually start SM2...
soundManager = new SoundManager();
soundManager.beginDelayedInit(); // ensure SM2 begins its init process, in the event dom ready / window.load() have already passed

Disabling debug output

SoundManager 2 will write to a debug <div> element or a javascript console if available, by default. To disable it, simply set the relevant property to false:

soundManager.debugMode = false;

To see related configuration code, refer to the source of this page which basically does all of the above "for real."


If SM2 is failing to start and throwing errors due to flash security, timeouts or other issues, check out the troubleshooting tool which can help you fix things.

No-debug, compressed version of soundmanager2.js

Once development is finished, you can also use the "minified" (60% smaller) version of SM2, which has debug output and comments removed for you: soundmanager2-nodebug-jsmin.js. If you can, serve this with gzip compression for even greater bandwidth savings!