videospeed/inject.js

chrome.extension.sendMessage({}, function(response) {
  var readyStateCheckInterval = setInterval(function() {
    if (document.readyState === 'complete') {
      clearInterval(readyStateCheckInterval);

      var tc = tc || {};
      tc.videoController = function(target) {
        this.video = target;
        this.initializeControls();

        chrome.storage.sync.get({
          speed: '1.00',
          rememberSpeed: false
        }, function(storage) {
          var speed = storage.rememberSpeed ? storage.speed : '1.00';
          target.playbackRate = speed;
          this.speedIndicator.textContent = speed;
        }.bind(this));

        this.video.addEventListener('ratechange', function(event) {
          var speed = this.getSpeed();
          this.speedIndicator.textContent = speed;
          chrome.storage.sync.set({
            'speed': speed
          });
        }.bind(this));
      };

      tc.videoController.prototype.getSpeed = function() {
        return parseFloat(this.video.playbackRate).toFixed(2);
      }

      tc.videoController.prototype.remove = function() {
        this.parentElement.removeChild(this);
      }

      tc.videoController.prototype.initializeControls = function() {
        var fragment = document.createDocumentFragment();
        var container = document.createElement('div');
        var speedIndicator = document.createElement('span');

        var controls = document.createElement('span');
        var fasterButton = document.createElement('button');
        var slowerButton = document.createElement('button');
        var rewindButton = document.createElement('button');

        rewindButton.innerHTML = '«';
        fasterButton.textContent = '+';
        slowerButton.textContent = '-';

        controls.appendChild(rewindButton);
        controls.appendChild(slowerButton);
        controls.appendChild(fasterButton);

        container.appendChild(speedIndicator);
        container.appendChild(controls);

        container.classList.add('tc-videoController');
        controls.classList.add('tc-controls');

        fragment.appendChild(container);
        this.video.parentElement.insertBefore(fragment, this.video);
        this.video.classList.add('tc-videoHost');

        this.speedIndicator = speedIndicator;

        container.addEventListener('click', function(e) {
          if (e.target === slowerButton) {
            runAction('slower')
          } else if (e.target === fasterButton) {
            runAction('faster')
          } else if (e.target === rewindButton) {
            runAction('rewind')
          } else {
            container.nextSibling.classList.add('vc-cancelled')
            container.remove();
          }

          e.preventDefault();
          e.stopPropagation();
        }, true);

        // Prevent full screen mode on YouTube
        container.addEventListener('dblclick', function(e) {
          e.preventDefault();
          e.stopPropagation();
        }, true);

        // Prevent full screen mode on Vimeo
        container.addEventListener('mousedown', function(e) {
          e.preventDefault();
          e.stopPropagation();
        }, true);
      }

      function runAction(action) {
        var videoTags = document.getElementsByTagName('video');
        videoTags.forEach = Array.prototype.forEach;

        videoTags.forEach(function(v) {
          if (!v.paused && !v.classList.contains('vc-cancelled')) {
            if (action === 'rewind') {
              v.playbackRate = Math.max(v.playbackRate - speedStep, 0.00);
              v.currentTime -= rewindTime;
            } else if (action === 'faster') {
              v.playbackRate += speedStep
            } else if (action === 'slower') {
              v.playbackRate = Math.max(v.playbackRate - speedStep, 0.00);
            }
          }
        });
      }

      document.addEventListener('keypress', function(event) {
        // if lowercase letter pressed, check for uppercase key code
        var keyCode = String.fromCharCode(event.keyCode).toUpperCase().charCodeAt();

        // Ignore keypress event if typing in an input box
        if (document.activeElement.nodeName === 'INPUT' && document.activeElement.getAttribute('type') === 'text') {
          return false;
        }

        if (keyCode == rewindKeyCode) {
          runAction('rewind')
        } else if (keyCode == fasterKeyCode) {
          runAction('faster')
        } else if (keyCode == slowerKeyCode) {
          runAction('slower')
        }

        return false;
      }, true);

      document.addEventListener('DOMNodeInserted', function(event) {
        var node = event.target || null;
        if (node && node.nodeName === 'VIDEO') {
          new tc.videoController(node);
        }
      });

      var videoTags = document.getElementsByTagName('video');
      videoTags.forEach = Array.prototype.forEach;
      videoTags.forEach(function(video) {
        var control = new tc.videoController(video);
      });

      var speedStep, rewindTime, rewindKeyCode, slowerKeyCode, fasterKeyCode;

      chrome.storage.sync.get({
          speedStep: 0.1, // default 0.10x
          rewindTime: 10, // default 10s
          rewindKeyCode: 65, // default: A
          slowerKeyCode: 83, // default: S
          fasterKeyCode: 68 // default: D
        },
        function(storage) {
          speedStep = Number(storage.speedStep);
          rewindTime = Number(storage.rewindTime);
          rewindKeyCode = Number(storage.rewindKeyCode);
          slowerKeyCode = Number(storage.slowerKeyCode);
          fasterKeyCode = Number(storage.fasterKeyCode);
        });
    }
  }, 10);
});