Show Hide Multiple Divs Based On One Div And Search Text?

I am going to achieve something like this.

<div id="sidebar">
<div id="html1"><h2>Test 1</h2></div>
<div id="html2"><h2>a1 tes2</h2></div>
<div id="html3"><h2>a2 tes3</h2></div>
</div>

The thing is that first I need to detect if the div id is "sidebar" if its "sidebar" then it will pickup all the text inside h2 tag and will search for a1 or a2 in the text.If a1 is found then it will pickup the id html2 and make this div only visible.So in this case it will pickup id html2 and make it visible while other ids like html1 and html3 will be hidden.