Automatic scroll the list of active item

[chintan944]

I have a list of 50 list item and accordingly 50 section on the page.all linked.

Left hand side the list of sections. On right side, the section container.

At once I can see 10 item on the window of left hand side. When I jump to 11 or any other sections of the list by scrolling on the right hand side then it makes it active list item on the left, but not visible visible or scroll automatically on the left hand side window the selected item of the list.