html内容
<div hidden id="keydiv">Hello World</div>
<btn class="btn btn-sm btn-default" onclick="copyText()">点此复制</btn>
js代码
function copyText() {
        var Url2 = document.getElementById("keydiv").innerText;
        var oInput = document.createElement(‘input‘);
        oInput.value = Url2;
        document.body.appendChild(oInput);
        oInput.select();
        document.execCommand("Copy"); 
        oInput.className = ‘oInput‘;
        oInput.style.display = ‘none‘;
        alert(‘复制成功‘);
    }
原文:https://www.cnblogs.com/ylblogss/p/9644532.html