js 浏览器复制功能

<!DOCTYPE html>
<html>
<head>
<title>复制到剪贴板</title>
<meta charset="utf-8">
</head>
<body>
<button onclick="copy('text-miao')"><b>复制到剪贴板</b></button>
<div id='text-miao'>今天你要嫁给我</div>
</body>
</html>
<script src="./jquery.js"></script>
<script type="text/javascript">
    function copy(id){
        //要复制的内容
        var msg = $('#'+id).text();
        try {
            var txtEl = document.createElement('textarea');
            txtEl.value = msg;
            document.body.appendChild(txtEl);
            txtEl.select(); // 选择对象
            document.execCommand("Copy"); // 执行浏览器复制命令
            txtEl.remove();
            alert('复制成功');
          } catch(err) {
            console.log(err);
          }
    }
</script>