what is use of each() function?

The internal pointer is advanced by the each() function while returning the key and value of the currently selected element. It should be noted that PHP 7.2 deprecates the each() function. A four-element array containing this element's key and value is returned.

The each() method designates a function to be executed for each element that matches. The loop can be terminated early by using return false.

Syntax:

\s$(selector).each(function(index,element))