addEventListener in content script not working
Content scripts do not run in the scope of the current page. The event handler has to be injected via another <script> tag, as described in this answer: Building a Chrome Extension with Youtube Events:
var actualCode = 'function onytplayerStateChange() {' + ' console.log("The state of the player has changed");' + '}';var script = document.createElement('script');script.textContent = actualCode;(document.head||document.documentElement).appendChild(script);script.parentNode.removeChild(script);PS. The DOM is available to the content script, so binding the event handler does work.