<div>

        <input type="text" name="guanfangaddress" id="guanfangaddress"/>

         <span id="copyBT" >复制</span>

</div>

<script type="text/javascript">

    function copyArticle(event) {

        const range = document.createRange();

        range.selectNode(document.getElementById('guanfangaddress'));

        const selection = window.getSelection();

        if(selection.rangeCount > 0) selection.removeAllRanges();

        selection.addRange(range);

        document.execCommand('copy');

        alert("复制成功！");

    }

    document.getElementById('copyBT').addEventListener('click', copyArticle, false);

</script>