title: Converting drop-down select input to radio buttons which require one to be chosen
body: <p>I'm using an e-commerce system which allows you to have several variations for each product - (for instance: large, medium, small t-shirts). However, we are having complaints from customers who add a t-shirt and ignore the variation. As a result, a lot of big people are getting small t-shirts (the default). To solve this, I'd like to force the user to choose a radio button (instead of a drop-down select list), and only then will the add to cart button become available. Here is the current php which displays the select drop-down;</p>
  
  <pre><code>&lt;?php while (have_variation_groups()) : the_variation_group(); ?&gt;
    &lt;?php /** variation HTML and loop */?&gt;
    &lt;select class='select_variation' name="variation[&lt;?php echo variation_id(); ?&gt;]" id="&lt;?php echo variation_group_form_id(); ?&gt;"&gt;
    &lt;?php while (have_variations()) : the_variation(); ?&gt;
       &lt;option value="&lt;?php echo the_variation_id(); ?&gt;"&gt;&lt;?php echo the_variation_name(); ?&gt;&lt;/option&gt;
     &lt;?php endwhile; ?&gt;
  &lt;/select&gt; 
  &lt;?php endwhile; ?&gt;
  &lt;?php echo add_to_cart_button(the_product_id()); ?&gt;
  </code></pre>
  
  <p>Which spits out this sort of html...</p>
  
  <pre><code>&lt;select class='select_variation' name="variation[1]" id="variation_select_22_1"&gt;
  &lt;option value="1"&gt;Small&lt;/option&gt;
  &lt;option value="2"&gt;Big&lt;/option&gt;
  &lt;/select&gt; 
  &lt;input type='submit' id='product_22_submit_button' class='buy_button' name='Buy'  value="Add To Cart" /&gt;
  </code></pre>
  
  <p>How would you suggest I convert the drop-down to radio button, and make sure the add-to-cart button is not clickable until they have chosen a variation?
  Thanks</p>