View all event listeners used in the page, getEventListeners(object) returns the event listeners registered on the specified object

getEventListeners.js

// Get all the binding click events number in page
// Return number
Array.from(document.querySelectorAll('*'))
  .reduce(function(pre, dom){
    var clks = getEventListeners(dom).click;
    pre += clks ? clks.length || 0 : 0;
    return pre
  }, 0)

// If you want see what events have been bound in all your elements in your page and 
// how many of the listeners of each of the events
Array.from(document.querySelectorAll('*'))
  .reduce(function(pre, dom){
    var evtObj = getEventListeners(dom)
    Object.keys(evtObj).forEach(function (evt) {
      if (typeof pre[evt] === 'undefined') {
        pre[evt] = 0
      }
      pre[evt] += evtObj[evt].length
    })
    return pre
  }, {})

// The result is like this:
{
  touchstart: 6,
  error: 2,
  click: 3249,
  longpress: 2997,
  tap: 2997,
  touchmove: 4,
  touchend: 4,
  touchcancel: 4,
  load: 1
}