chrome.tabs.onUpdated.addListener(
  function(tabId, changeInfo, tab) {
    if (youtube_parser(changeInfo.url)) {
      chrome.tabs.sendMessage( tabId, {
        message: 'ytvideo',
        url: changeInfo.url
      })
    }
  }
);
function youtube_parser(url) {
    var regExp = /^.*((youtu.be\/)|(v\/)|(\/u\/\w\/)|(embed\/)|(watch\?))\??v?=?([^#\&\?]*).*/;
    var match = url.match(regExp);
    return (match && match[7].length == 11) ? match[7] : false;
}