It makes a deep copy of everything It makes a shallow copy: a new array, but the same object references inside it It makes b a reference to a It copies only the first element
Removing all listeners Assigning events to another developer Attaching one listener to a parent element and handling events from its children through bubbling, using event.target Firing events on a timer
undefined A single accumulated value The original array, modified in place A new array with the callback's result for each element; the original array is unchanged
It is a JavaScript runtime built on V8 that uses an event-driven, non-blocking I/O model, mainly for server-side code It is a browser It is a front-end CSS framework It runs only in Chrome
It is the same as fixed It works only on images The element acts as relatively positioned until a scroll threshold is reached, then sticks like a fixed element within its container It removes the element from the flow
It lets the browser choose an appropriately sized image for the screen's resolution and size It defines CSS styles It sets the alt text It loads all the images at once
Cookies are sent to the server with every matching HTTP request; localStorage stays in the browser and is never sent automatically localStorage is sent; cookies are not Both are sent with every request Neither is ever accessible to JavaScript
