js

deleteFromDocument()

html

<p>
  Try highlighting some of the text in this paragraph. Once you do, you can
  remove the selected content by clicking the button below.
</p>
<button>Delete selected text</button>

js

let button = document.querySelector("button");
button.addEventListener("click", deleteSelection);

function deleteSelection() {
  let selection = window.getSelection();
  selection.deleteFromDocument();
}