How to force scroll in inner div rather than browser window?

Question

In the markup below, when I minimizes the browser window, I see scroll in the browser window scrolling rather than the scroll within the div from the overflow-y: scroll. How can I make it scroll in the inner scroll without doing anything to the body element?

<div style="overflow-y: scroll;">
line<br/>
line<br/>
line<br/>
line<br/>
line<br/>
line<br/>
</div>

Answer 1

Set the height of the <div>

<div style="height:50px; overflow-y: scroll;">