html:

     
      这是要复制的1内容
     
这是复制按钮

js:

function copyArticle() {                const range = document.createRange();                range.selectNode(document.getElementById('copyBT'));                const selection = window.getSelection();                if (selection.rangeCount > 0) selection.removeAllRanges();                selection.addRange(range);                document.execCommand('copy');                alert("复制成功")            }            document.getElementById('contentas').addEventListener('click', copyArticle, false);