javascript - 如何将事件监听器添加到在原型(prototype)中动态创建的元素？

Question

HTML

<div id="main"></div>

JS

var TestClass = function() {};
TestClass.prototype = {
    addElement: function(parentId) {
    var parent = document.querySelector('#' + parentId);
    var a = document.createElement('a');
    a.textContent = '+';
    a.href = '#';
    a.addEventListener('click', this.onElementClick, false); //nothing happens on click
    parent.innerHTML = a.outerHTML;
  },

  onElementClick: function() {
    console.log('dynamic element clicked');
  }
};

new TestClass().addElement('main'); // on DOM ready

输出

<div id="main"><a href="#">+</a></div>

Answer 1

像这样:

var TestClass = function() {};
TestClass.prototype = {
    addElement: function(parentId) {
    var parent = document.getElementById(parentId); //Changed to getElementById
    var a = document.createElement('a');
    a.textContent = '+';
    a.href = '#';
    a.addEventListener('click', this.onElementClick, false);
    parent.append(a); //Changed
  },

  onElementClick: function() {
    console.log('dynamic element clicked');
  }
};

new TestClass().addElement('main'); // on DOM ready

<div id="main"></div>

您没有将 a 添加到 parent，而只是添加了它的 HTML。