Validation - no selection show validation div

Validation - no selection show validation div

Hi gang,

I'm trying to show a div if a selection isn't made.

Div:
  1. <div id="Q1REQANS" class="validation-error" style="display:none;">Please answer question 1 before continuing.</div>
My simple yes/no question:
  1. <div class="response-set">
      <span id="Q1C1"><input type="radio" name="Q1" value="1" id="Q1_1" /> <span class="choice-text">Yes</span><br /></span>
      <span id="Q1C2"><input type="radio" name="Q1" value="2" id="Q1_2" /> <span class="choice-text">No</span><br /></span>
    </div>



My jsfiddle link:

http://jsfiddle.net/Luck12/j3BPz/

Kind regards