I am trying to pass some JavaScript variables that I have assigned to form variables into a query string used by a jQuery plug in called fancybox. If I hard code in the string that I want lightbox works great, however I need it to pass some form values in there to make it work as desire.

<script type="text/javascript">
    $(document).ready(function(){

            var item = document.itemFinder.item;
            var zip = document.itemFinder.zip;
            var radius = document.itemFinder.radius;
            var dataString = "item=" + item + "&zip=" + zip + "&radius=" + radius;
            $("#various3").fancybox({
                    ajax : { type   : "POST", data  : dataString},
                    'scrolling'         : 'auto',
                    'overlayOpacity'    : '0'           
                    }               
                );
    });
    </script>

What am I doing wrong?