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">
<label><input type="radio" name="group1" checked="checked" value="one" /> one </label>
<label><input type="radio" name="group1" value="two" /> two </label>
<fieldset id="one" class="sets"> one </fieldset>
<fieldset id="two" class="sets"> two </fieldset>
JavaScript
$("input[name=group1]").change(function() {
$(".sets").hide();
$("#" + this.value).show();
}).filter(':checked').change();