You can add a listener to the “paste” event and reformat the clipboard contents. Like so:
let editableDiv = document.querySelector('div[contenteditable="true"]');
editableDiv.addEventListener("paste", function(e) {
e.preventDefault();
var text = e.clipboardData.getData("text/plain");
document.execCommand("insertHTML", false, text);
});
Here another example for all containers in the body:
let allEditableDivs = document.querySelectorAll('div[contenteditable="true"]');
[].forEach.call(allEditableDivs, function (el) {
el.addEventListener('paste', function(e) {
e.preventDefault();
var text = e.clipboardData.getData("text/plain");
document.execCommand("insertHTML", false, text);
}, false);
}
Saludos.