preventDefault() & stopPropagation() — JS Technical Interview Questions & Answers

Stopping default browser behaviour and event bubbling.

preventDefault() & stopPropagation()

  • preventDefault() & stopPropagation() (js) is a JS topic. In plain words you use it for a short preventDefault & stopPropagation js example in a script in the browser. Don’t start with a slogan — start with that picture.
  • Smallest example: the smallest preventDefault & stopPropagation js example you can type. Type it, run it, and say what you see. If you can do that from memory, you know preventDefault() & stopPropagation() (js).
  • From the example next to this theory: Stopping default browser behaviour and event bubbling.
  • Trap: only saying “preventDefault & stopPropagation js” with no example. Fix that before you talk about advanced JS.
  • Viva: what is preventDefault() & stopPropagation() (js)? Then show the smallest preventDefault & stopPropagation js example you can type. Then name the trap.

Technical Interview Tip: What is preventDefault() & stopPropagation() (js)? Show this: the smallest preventDefault & stopPropagation js example you can type. Trap: only saying “preventDefault & stopPropagation js” with no example.

Code Examples for preventDefault() & stopPropagation()

preventDefault() & stopPropagation() — working example

// Browser delegation sketch:
// list.addEventListener("click", (e) => {
//   if (e.target.matches("button.del")) {
//     e.preventDefault();
//     e.target.closest("li")?.remove();
//   }
// });

// Runnable stand-in:
function onClick(e) {
  if (e.target === "del") {
    e.preventDefault?.();
    return "removed";
  }
  return "ignored";
}
console.log(onClick({ target: "del", preventDefault() { this.ok = true; } }));

preventDefault() & stopPropagation() — listeners react to events; delegation handles many children from one parent; preventDefault stops default browser action.

How to Explain preventDefault() & stopPropagation() to an Interviewer

What is preventDefault() & stopPropagation() (js)?

Used for a short preventDefault & stopPropagation js example a script in the browser Not just the heading

Give one small example of preventDefault() & stopPropagation() (js).

the smallest preventDefault & stopPropagation js example you can type Stopping default browser behaviour and event bubbling

What mistake do beginners make with preventDefault() & stopPropagation() (js)?

only saying “preventDefault & stopPropagation js” with no example Show the fix

Where do you use preventDefault() & stopPropagation() (js)?

a script in the browser a short preventDefault & stopPropagation js example