处理默认右键复制，添加额外内容

<div id="wrap">这是复制的复制内容</div><script>var wrap = document.getElementById('wrap')wrap.oncopy = function (event) {// 通过copy事件监听，阻止将选中内容复制到系统剪切板上event.preventDefault()// 获取选中内容对象const selection = document.getSelection()// selection对象重构了toSring()方法，获取selection对象的选中内容var selectContent = selection.toString()var dealContent =selectContent +'转载请联系作者，内容地址：xxxxx'// 把重写后的内容写入到剪贴板event.clipboardData.setData('text/plain', dealContent)}</script>