Question

What will happen when the data of the jQuery.cache is read from an element?

(a) Unique number is retrieved as elem[jQuery.expando]

(b) Data is read from jQuery.cache[id]

(c) Unique number is retrieved as elem[jQuery.expando] & Data is read from jQuery.cache[id]

(d) Data is cleared from jQuery.cache[id]

I have been asked this question during an interview.

Enquiry is from JavaScript and Memory Leak topic in chapter Caching, Debugging and Animation of JavaScript

Answer 1

The correct choice is (c) Unique number is retrieved as elem[jQuery.expando] & Data is read from jQuery.cache[id]

The explanation is: jQuery.cache[id] is used to associate handlers and other data with elements. When the data is read from an element:

The element unique number is retrieved from id = elem[ jQuery.expando].

The data is read from jQuery.cache[id].