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">
<fieldset><legend>Link</legend><span>CHECK</span></fieldset>
CSS
span { display: none; }
JavaScript
$("legend").click(function(){
$(this).siblings("span").show();
});