Test if HTML5 video autoplay is supported

isAutoplaySupported.js

// isAutoplaySupported(callback);
// Test if HTML5 video autoplay is supported
isAutoplaySupported = function(callback) {
  // Is the callback a function?
  if (typeof callback !== 'function') {
    console.log('isAutoplaySupported: Callback must be a function!');
    return false;
  }
  // Check if sessionStorage exist for autoplaySupported,
  // if so we don't need to check for support again
  if (!sessionStorage.autoplaySupported) {
    // Create video element to test autoplay
    var video = document.createElement('video');
    video.autoplay = true;
    video.src = 'data:video/mp4;base64,AAAAIGZ0eXBtcDQyAAAAAG1wNDJtcDQxaXNvbWF2YzEAAATKbW9vdgAAAGxtdmhkAAAAANLEP5XSxD+VAAB1MAAAdU4AAQAAAQAAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAgAAACFpb2RzAAAAABCAgIAQAE////9//w6AgIAEAAAAAQAABDV0cmFrAAAAXHRraGQAAAAH0sQ/ldLEP5UAAAABAAAAAAAAdU4AAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAABAAAAAAoAAAAFoAAAAAAAkZWR0cwAAABxlbHN0AAAAAAAAAAEAAHVOAAAH0gABAAAAAAOtbWRpYQAAACBtZGhkAAAAANLEP5XSxD+VAAB1MAAAdU5VxAAAAAAANmhkbHIAAAAAAAAAAHZpZGUAAAAAAAAAAAAAAABMLVNNQVNIIFZpZGVvIEhhbmRsZXIAAAADT21pbmYAAAAUdm1oZAAAAAEAAAAAAAAAAAAAACRkaW5mAAAAHGRyZWYAAAAAAAAAAQAAAAx1cmwgAAAAAQAAAw9zdGJsAAAAwXN0c2QAAAAAAAAAAQAAALFhdmMxAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAoABaABIAAAASAAAAAAAAAABCkFWQyBDb2RpbmcAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP//AAAAOGF2Y0MBZAAf/+EAHGdkAB+s2UCgL/lwFqCgoKgAAB9IAAdTAHjBjLABAAVo6+yyLP34+AAAAAATY29scm5jbHgABQAFAAUAAAAAEHBhc3AAAAABAAAAAQAAABhzdHRzAAAAAAAAAAEAAAAeAAAD6QAAAQBjdHRzAAAAAAAAAB4AAAABAAAH0gAAAAEAABONAAAAAQAAB9IAAAABAAAAAAAAAAEAAAPpAAAAAQAAE40AAAABAAAH0gAAAAEAAAAAAAAAAQAAA+kAAAABAAATjQAAAAEAAAfSAAAAAQAAAAAAAAABAAAD6QAAAAEAABONAAAAAQAAB9IAAAABAAAAAAAAAAEAAAPpAAAAAQAAE40AAAABAAAH0gAAAAEAAAAAAAAAAQAAA+kAAAABAAATjQAAAAEAAAfSAAAAAQAAAAAAAAABAAAD6QAAAAEAABONAAAAAQAAB9IAAAABAAAAAAAAAAEAAAPpAAAAAQAAB9IAAAAUc3RzcwAAAAAAAAABAAAAAQAAACpzZHRwAAAAAKaWlpqalpaampaWmpqWlpqalpaampaWmpqWlpqalgAAABxzdHNjAAAAAAAAAAEAAAABAAAAHgAAAAEAAACMc3RzegAAAAAAAAAAAAAAHgAAA5YAAAAVAAAAEwAAABMAAAATAAAAGwAAABUAAAATAAAAEwAAABsAAAAVAAAAEwAAABMAAAAbAAAAFQAAABMAAAATAAAAGwAAABUAAAATAAAAEwAAABsAAAAVAAAAEwAAABMAAAAbAAAAFQAAABMAAAATAAAAGwAAABRzdGNvAAAAAAAAAAEAAAT6AAAAGHNncGQBAAAAcm9sbAAAAAIAAAAAAAAAHHNiZ3AAAAAAcm9sbAAAAAEAAAAeAAAAAAAAAAhmcmVlAAAGC21kYXQAAAMfBgX///8b3EXpvebZSLeWLNgg2SPu73gyNjQgLSBjb3JlIDE0OCByMTEgNzU5OTIxMCAtIEguMjY0L01QRUctNCBBVkMgY29kZWMgLSBDb3B5bGVmdCAyMDAzLTIwMTUgLSBodHRwOi8vd3d3LnZpZGVvbGFuLm9yZy94MjY0Lmh0bWwgLSBvcHRpb25zOiBjYWJhYz0xIHJlZj0zIGRlYmxvY2s9MTowOjAgYW5hbHlzZT0weDM6MHgxMTMgbWU9aGV4IHN1Ym1lPTcgcHN5PTEgcHN5X3JkPTEuMDA6MC4wMCBtaXhlZF9yZWY9MSBtZV9yYW5nZT0xNiBjaHJvbWFfbWU9MSB0cmVsbGlzPTEgOHg4ZGN0PTEgY3FtPTAgZGVhZHpvbmU9MjEsMTEgZmFzdF9wc2tpcD0xIGNocm9tYV9xcF9vZmZzZXQ9LTIgdGhyZWFkcz0xMSBsb29rYWhlYWRfdGhyZWFkcz0xIHNsaWNlZF90aHJlYWRzPTAgbnI9MCBkZWNpbWF0ZT0xIGludGVybGFjZWQ9MCBibHVyYXlfY29tcGF0PTAgc3RpdGNoYWJsZT0xIGNvbnN0cmFpbmVkX2ludHJhPTAgYmZyYW1lcz0zIGJfcHlyYW1pZD0yIGJfYWRhcHQ9MSBiX2JpYXM9MCBkaXJlY3Q9MSB3ZWlnaHRiPTEgb3Blbl9nb3A9MCB3ZWlnaHRwPTIga2V5aW50PWluZmluaXRlIGtleWludF9taW49Mjkgc2NlbmVjdXQ9NDAgaW50cmFfcmVmcmVzaD0wIHJjX2xvb2thaGVhZD00MCByYz0ycGFzcyBtYnRyZWU9MSBiaXRyYXRlPTExMiByYXRldG9sPTEuMCBxY29tcD0wLjYwIHFwbWluPTUgcXBtYXg9NjkgcXBzdGVwPTQgY3BseGJsdXI9MjAuMCBxYmx1cj0wLjUgdmJ2X21heHJhdGU9ODI1IHZidl9idWZzaXplPTkwMCBuYWxfaHJkPW5vbmUgZmlsbGVyPTAgaXBfcmF0aW89MS40MCBhcT0xOjEuMDAAgAAAAG9liIQAFf/+963fgU3DKzVrulc4tMurlDQ9UfaUpni2SAAAAwAAAwAAD/DNvp9RFdeXpgAAAwB+ABHAWYLWHUFwGoHeKCOoUwgBAAADAAADAAADAAADAAAHgvugkks0lyOD2SZ76WaUEkznLgAAFFEAAAARQZokbEFf/rUqgAAAAwAAHVAAAAAPQZ5CeIK/AAADAAADAA6ZAAAADwGeYXRBXwAAAwAAAwAOmAAAAA8BnmNqQV8AAAMAAAMADpkAAAAXQZpoSahBaJlMCCv//rUqgAAAAwAAHVEAAAARQZ6GRREsFf8AAAMAAAMADpkAAAAPAZ6ldEFfAAADAAADAA6ZAAAADwGep2pBXwAAAwAAAwAOmAAAABdBmqxJqEFsmUwIK//+tSqAAAADAAAdUAAAABFBnspFFSwV/wAAAwAAAwAOmQAAAA8Bnul0QV8AAAMAAAMADpgAAAAPAZ7rakFfAAADAAADAA6YAAAAF0Ga8EmoQWyZTAgr//61KoAAAAMAAB1RAAAAEUGfDkUVLBX/AAADAAADAA6ZAAAADwGfLXRBXwAAAwAAAwAOmQAAAA8Bny9qQV8AAAMAAAMADpgAAAAXQZs0SahBbJlMCCv//rUqgAAAAwAAHVAAAAARQZ9SRRUsFf8AAAMAAAMADpkAAAAPAZ9xdEFfAAADAAADAA6YAAAADwGfc2pBXwAAAwAAAwAOmAAAABdBm3hJqEFsmUwIK//+tSqAAAADAAAdUQAAABFBn5ZFFSwV/wAAAwAAAwAOmAAAAA8Bn7V0QV8AAAMAAAMADpkAAAAPAZ+3akFfAAADAAADAA6ZAAAAF0GbvEmoQWyZTAgr//61KoAAAAMAAB1QAAAAEUGf2kUVLBX/AAADAAADAA6ZAAAADwGf+XRBXwAAAwAAAwAOmAAAAA8Bn/tqQV8AAAMAAAMADpkAAAAXQZv9SahBbJlMCCv//rUqgAAAAwAAHVE=';
    video.load();
    video.style.display = 'none';
    video.playing = false;
    video.play();
    // Check if video plays
    video.onplay = function() {
      this.playing = true;
    };
    // Video has loaded, check autoplay support
    video.oncanplay = function() {
      if (video.playing) {
        sessionStorage.autoplaySupported = 'true';
        callback(true);
      } else {
        sessionStorage.autoplaySupported = 'false';
        callback(false);
      }
    };
  } else {
    // We've already tested for support
    // use sessionStorage.autoplaySupported
    if (sessionStorage.autoplaySupported === 'true') {
      callback(true);
    } else {
      callback(false);
    }
  }
}

// Usage: isAutoplaySupported(callback);
// Using a callback assures that support
// has been properly checked
isAutoplaySupported(function(supported) {
  if (supported) {
    // HTML5 Video Autoplay Supported!
    console.log('HTML5 Video Autoplay Supported!');
  } else {
    // HTML5 Video Autoplay Not Supported :(
    console.log('HTML5 Video Autoplay Not Supported :(');
  }
});

is the play event gauranteed to fire before the canplay event?

See if it is more reliable

If it's jQuery related, it cannot be.

If this is being imported as a module then it ends up with an error because window.sessionStorage is not available. Are there any solutions to this? Can the value be stored somewhere other than window.sessionstorage? Somewhere in document maybe?