There is no append support without reparsing the whole innerHTML. This makes changing innerHTML directly very slow.
For example, for appending to a html tag, you'll need to do the following −
let myDiv = document.querySelector('#myDiv') // Reparses the whole myDiv tag. myDiv.innerHTML += '<p>Added new tag</p>'
innerHTML does not provide validation and therefore we can potentially insert valid and broken HTML in the document and break it.