JavaScript Interview Question #65

What does event.preventDefault() do?

DOM, Events & Event Loop Fundamentals Mid-Level Intermediate

Quick Interview Answer

preventDefault asks the browser not to perform the event's normal default action when that action is cancelable. For example, it can prevent a form submission or stop a link from navigating.

Detailed Explanation

preventDefault asks the browser not to perform the event's normal default action when that action is cancelable. For example, it can prevent a form submission or stop a link from navigating.

It does not stop the event from propagating. If propagation also needs to be stopped, that is a separate decision using stopPropagation.

Code Example

const form = document.querySelector("#loginForm");

form.addEventListener("submit", event => {
    event.preventDefault();

    // Validate and submit using application logic.
    console.log("Default form submission prevented");
});