https://www.w3schools.com/js/tryit.asp?filename=tryjs_change_innerhtml

received: function(data) {
// Called when there‘s incoming data on the websocket for this channel
// document.getElementById("notifications").innerHTML = data.html;
// ??的只是取代，不能增加節點，我像知道如何增加子節點。
$("#notifications").prepend(data.html);

如何用原生js寫出$("#notifications").prepend(data.html);

備註：ActionCable.server.broadcast "notifications:11",

　　　　　　{html: "<div>Hello world</div>"}

javascript 語法問題：