Pattern Input

pattern-input.js

let pattern = "[a-zöçşiğü]*";
let oldValue = "";
let oldPosition = 0;

document.getElementById("#test").addEventListener('keydown', function(event) {
	oldPosition = event.target.selectionStart;
	oldValue = event.target.value;
});

document.getElementById("#test").addEventListener('input', function(event) {
	let parts = event.target.value.match(new RegExp(pattern, "gi"));
  event.target.value = parts ? parts.join("") : "";
  if (oldValue != event.target.value) oldPosition = oldPosition + 1;
  event.target.setSelectionRange(oldPosition, oldPosition);
});