on scroll code example

Example 1: js onscroll event

// HTML:
<element onscroll="myScript">
// JavaScript:
object.addEventListener("scroll", myScript)
// or
object.onscroll = function() { /*...*/ }

Example 2: jquery on wheel event

$("#main-div" ).on( 'wheel', function() {
   alert("Hello! I am an alert box!!");
});

Example 3: jquery on scroll

Syntax
Trigger the scroll event for the selected elements:
$(selector).scroll()

Attach a function to the scroll event:
$(selector).scroll(function)