好，我知道这可行:

let elem = document.querySelector ( 'css-selector (id or class)' )

那应该给你你的元素.然后，您可以这样做:

That should give you your element. Then you do this:

elem.innerHTML = elem.innerHTML + myNewStuff;

这会将您的html附加到该元素的innerHTML上.我很快尝试了一下，它起作用了.

That'll append your html to the innerHTML of the element. I tried it quickly, it works.