What advantage does 'beforeinput' have over 'input' for validation?
input.addEventListener('beforeinput', e => {
if (!/^\d*$/.test(e.data)) {
e.preventDefault();
}
});
The 'beforeinput' event offers preventive validation because: 1) It fires before the input value changes, 2) Allows preventing invalid input entirely using preventDefault(), 3) Provides access to the proposed input through e.data, 4) Creates better user experience by preventing invalid characters rather than showing errors, 5) Works with all input methods including paste, drag-drop, and IME input. This is more user-friendly than cleaning up invalid input after the fact.