如何将函数绑定到Shadow DOM内的元素？

Question

我正在使用Web Components并尝试将click事件绑定到Shadow DOM内部的元素.

1. component.html包含<link rel="import" ...>在index.html内部

<template id="my-element">
    <section>
        <header>
            <content select="h1"></content>
            <button></button>
        </header>
        <content select="div"></content>
    </section>
</template>

2.后期元素用法:

<my-element>
    <h1>Headline</h1>
    <div>...</div>
</my-element>

3.访问元素并将函数绑定到它

现在我想在我的内部添加一个(不幸的是隐藏了).喜欢:addEventListener()<button><my-element> #shadow-root

var elemBtn = document.querySelector('my-element button');
elemBtn.addEventListener('click', function(event) {
    // do stuff
});

但那不行.我如何实现这一目标？

Answer 1

您应该能够在不涉及窗口对象的情况下执行此操作.这是一个完整的例子:

<!-- Define element template -->
<template>
  <h1>Hello World</h1>
  <button id="btn">Click me</button>
</template>

<!-- Create custom element definition -->
<script>
  var tmpl = document.querySelector('template');

  var WidgetProto = Object.create(HTMLElement.prototype);

  WidgetProto.createdCallback = function() {
    var root = this.createShadowRoot();
    root.appendChild(document.importNode(tmpl.content, true));
    // Grab a reference to the button in the shadow root
    var btn = root.querySelector('#btn');
    // Handle the button's click event
    btn.addEventListener('click', this.fireBtn.bind(this));
  };

  // Dispatch a custom event when the button is clicked
  WidgetProto.fireBtn = function() {
    this.dispatchEvent(new Event('btn-clicked'));
  };

  var Widget = document.registerElement('my-widget', {
    prototype: WidgetProto
  });
</script>

<!-- Use the element -->
<my-widget></my-widget>

<!-- Listen for its click event -->
<script>
  var widget = document.querySelector('my-widget');
  widget.addEventListener('btn-clicked', function() {
    alert('the button was clicked');
  });
</script>

关于jsbin的例子