How did they make IXL

Question

On IXL, they have a lot of different topics.
So for each topic question: For example:
Multiple choices: what is 1 + 1?
A, 5
B, 1
C, 2
D, 3
The answer is C.
So do they add event listeners for C, and for the other ones (A, B, D) to test if wrong?
My point is, there are a lots of questions and Topics, + for every grade, + for different subjects.
Like .. that would be lots and lots of event listeners.
So did they do it like I was thinking (all with event listeners),
or did they have a different technique?

Answer 1

Go through this series from #1 to #6.
Read all the reference material.

Tag us here if you don't understand anything in this series.

https://www.sololearn.com/post/129437/?ref=app

https://code.sololearn.com/WKKkpq0efxai/?ref=app

Answer 2

It only has one form submit listener

Answer 3

The website is built using the YUI js and css framework, along with other JS libraries. This allows event listeners to be applied dynamically to many different targets without hard coding needed.