which on is indicated by jQuery.scrollTop?
<p>i have confuse about a value returned from <code>jQuery.scrollTop()</code>.</p>

<p>which node indicates <code>jQuery.scrollTop()</code>?
the red one or green?</p>

<p><a href="https://i.stack.imgur.com/etKAT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/etKAT.png" alt="the screen shot"></a></p>