var _ytmp3 = {
  writeBtn : function(){
    var clk = "window.open('http://www.youtube-mp3.org/redir?url='+encodeURIComponent(window.location))";
    var obj = document.getElementById('watch7-secondary-actions');
    if (obj) {
      obj.innerHTML = obj.innerHTML +
              '<button id="ytmp3Mp3Download" class="yt-uix-button yt-uix-tooltip" onclick="'+clk+'" type="button">'+
              '<span class="yt-uix-button-content">Download mp3</span>'+
              '</button>';
    } else {
        var obj = document.getElementById('watch-actions');
        if (obj) {
          obj.innerHTML = obj.innerHTML +
                  '<button id="ytmp3Mp3Download" class="yt-uix-button yt-uix-tooltip" onclick="'+clk+'" type="button">'+
                  '<span class="yt-uix-button-content">Download mp3</span>'+
                  '</button>';
        }
    }
  },

  checkForMissingBtn : function(){
      if(!document.getElementById('ytmp3Mp3Download')) {
        this.writeBtn();
      }

      window.setTimeout(function(){this.checkForMissingBtn()}, 750);
  },

  init : function(){
    this.writeBtn();
    this.checkForMissingBtn();
  },
};

_ytmp3.init();