@CharlieJustUs when you use Fiddle is automatically sets the $ variable for you. When your script tries to run on your site, that variable is not set, and it fails.
Try this please.
jQuery(document).ready(function($) {
$(function() {
$('ul.clearfix').each(function() {
var $select = $('<select class="dropdown-toggle" />');
$(this).find('a').each(function() {
var $option = $('<option />');
$option.attr('value', $(this).attr('href')).html($(this).html());
$select.append($option);
});
$(this).replaceWith($select);
});
});
// This will grab the value the select is being set to and redirect to the link
$('select.dropdown-toggle').on('change', function(){
window.location.href = $( this ).val();
});
});