hover over a div and adjacent div changes color
<b>sibling method:</b>
<div>
<div class="sibling-hover">hover over me</div>
<div>I do nothing</div>
<div>I do nothing</div>
<div class="sibling-highlight">I get highlighted</div>
</div>
<b>child method:</b>
<div id="parent">
<div>hover over me</div>
<div>hover over me</div>
<div>hover over me</div>
<div class="parent-highlight">I get highlighted</div>
</div>