<script type="text/javascript">
function setScrollbarTrackColor()
document.body.style.scrollbarTrackColor="pink";
<input type="button" onclick="setScrollbarTrackColor()" value="Set ScrollbarTrackColor" />
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>
<p>An example paragraph</p>