SO fiddle
Test Fiddle mainly for SO Questions
by Nick Craver
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<input type="checkbox" id="test" class="cb" />
<input type="checkbox" id="test2" class="cb"/>
<div id="example">Example</div>
<div id="example2">Example2</div>
JavaScript
$(document).ready(function(){
$(".cb").change(function() {
$("#" + this.id.replace('test', 'example')).toggle(this.checked);
}).change();
});