Checkbox to dropdown

Hi, how can I change the checkboxes into dropdown? And remain the default setting of the checkboxes. What I mean is, all values are already displayed when the page is visited. Here’s the link: http://bit.do/bLNZx

I have js that will convert the checkbox into dropdown, but the default setting is lost.

(function($){
	"use strict"

	$(function(){
		var $job_types_select = $('<select class="job_types_select"></select>');
		var $job_types_ul = $('form.job_filters ul.job_types');
		var $job_type_hidden = $('<input type="hidden" name="filter_job_type[]"/>');
			$job_types_ul.find('li').each(function(){
				var $li = $(this);
				var label_text = $li.find('label').text();
				var value = $li.find('input:checkbox').val();
				var $option = $('<option></option>');
				$option.text(label_text);
				$option.attr({value: value});
				$job_types_select.append($option);
				});
				$job_types_select.change(function(){
				var value = $(this).val();
				$('input:hidden[name="filter_job_type[]"]').val(value);
					var target = $(this).closest('div.job_listings');
					target.triggerHandler('update_results', [ 1, false ]);
				});
		$job_types_ul.after($job_type_hidden);
		$job_types_ul.replaceWith($job_types_select);
	});
})(jQuery);

https://wordpress.org/plugins/wp-job-manager/