I have two checkboxes and one of the checkboxes must be checked. I can see that it's right, no syntax errors. What should be made to my code to check if none of the checkboxes were checked?

HTML :

```
<input type="checkbox" value="aa" class="first" name="a"> Yes<br/>
<input type="checkbox" value="bb" class="second" name="b"> No <br/>
<button type="submit">Go!</button>
<p class="error"></p>

```

JavaScript:

```
$('button').on('click',function(){
    if( $(".first:not(:checked)") && $(".second:not(:checked)") ){
        $('.error').text('You must select atleast one!');
    }else
        $('.error').hide();
});

```

Example : <http://jsfiddle.net/ptbTq/>