Filters a select field based a selection from another.

jquery.filterBy.custom.js

$(document).ready(function() {
    $('.search select#search_tour_stop').filterBy('.search select#search_year');
}


jQuery.fn.filterBy = function(watch) {
	options = new Array;
	target  = $(this);

	target.find('option').each(function(index, option) {
		if (index > 0) {
			options.push( { filter: $(option).text().match(/\.(\d{2}) -/)[1], element: option } );
		}
	});

	el = $(watch);
	el.change(function () {
		selected = $(watch +" option:selected");
		value 	 = selected.val().slice(2);
		
		target.html('');

		$.each(options, function(index, option) { 
			if (option.filter === value) {
				target.append(option.element);
			}
		});
	});
	
	el.trigger('change');
};

jquery.filterBy.js

$(document).ready(function() {
    $('.search select#search_tour_stop').filterBy('.search select#search_year', 'data-filter');
}


jQuery.fn.filterBy = function(watch, attr) {
	options = new Array;
	target  = $(this);

	target.find('option').each(function(index, option) {
		if (index > 0) {
			options.push( { filter: $(option).attr('data-filter'), element: option } );
		}
	});

	el = $(watch);
	el.change(function () {
		selected = $(watch +" option:selected");
		value 	 = selected.attr(attr);
		
		target.html('');

		$.each(options, function(index, option) { 
			if (option.filter === value) {
				target.append(option.element);
			}
		});
	});
	
	el.trigger('change');
};