outerHTML is a property of a node element that permits to
outerHTML replaces the entire target element with the returned content while innerHTML puts the content inside the target element .
let htmlFragment = "<body><p>Replacing the whole body node content with a paragraph</p></body>";
document.body.outerHTML += htmlFragment
If you want to insert a HTML fragment and not delete the actual tree, you can use InsertAdjacentHTML
script elements inserted using outerHTML do not execute when they are inserted. 1)