How to make an array of items which are checked in checkbox [duplicate]

This question already has an answer here:

• Best way to get all selected checkboxes VALUES in jQuery [duplicate] 1 answer

I have some 20 check boxes ( dynamic number) in a HTML page which is checked by default. A user can uncheck it or leave it checked. At the end, there is a button to submit.

How to get the items that are only checked at the time of submitting?