纯JS实现，支持移动端和PC。clipboard.js

1. 引入clipboard.js

<script type="text/javascript" src="/public/js/clipboard.min.js"></script>

2. html

<!-- Target -->
<input id="foo" value="https://github.com/zenorocha/clipboard.js.git">

<!-- Trigger -->
<button class="btn" data-clipboard-target="#foo">
    ![](assets/clippy.svg)
</button>

3. JS

<script type="text/javascript">
  var clipboard = new Clipboard('.btn');
</script>

具体可以查看官网的例子
https://clipboardjs.com/
https://github.com/zenorocha/clipboard.js