How to create page scroll indicator progress bar in JavaScript

Scrolling indicator progress bar which trace the page scrolling position scrolling towards down and towards up the scroll track bar will be showing the progress bar at the top of home screen. there are JavaScript function which handle the page length scroll bar. it is fully responsive resize the browser to see responsiveness the page length will be increase at small screen.

Let's create JavaScript scroll indicator for beginner to advance which indicate the scroll bar of page it is also called page scroll indicator.