code: function _Debugger_updateBlocker(oldBlocker, newBlocker) {
      if (oldBlocker === newBlocker) return;
  
      var oldEvents = _Debugger_blockerToEvents(oldBlocker);
      var newEvents = _Debugger_blockerToEvents(newBlocker);
  
      // remove old blockers
      for (var i = 0; i < oldEvents.length; i++) {
        document.removeEventListener(oldEvents[i], _Debugger_blocker, true);
      }
  
      // add new blockers
      for (var i = 0; i < newEvents.length; i++) {
        document.addEventListener(newEvents[i], _Debugger_blocker, true);
      }
    }
docs: BLOCK EVENTS