(function($) {

	var keyup = 38, keydown= 40, enter = 13, tab = 9;
	var activeOptions = null;

    $.fn.dropdown = function() {

        this.each(function() {
			var selectControl = this;

			var selected = $('<input>').addClass('dropdown').click(function(event) { event.stopPropagation();
			    var dropdown = $(this).prev(); // the ol with options
			    hideActiveDropdown();
			    var p = $(this).position();
			    selected.focus();
			    dropdown.css('left', (p.left -4) + 'px').css('top', (p.top + 1) + $(this).outerHeight() + 'px').removeClass('hidden');
			    activeOptions = dropdown;
			}).keydown(function(event) {

			    if (event.keyCode != tab) event.preventDefault();

				switch (event.keyCode) {
					case keyup:
						selectItem($('option:selected', selectControl).prev());
						break;
					case keydown:
						selectItem($('option:selected', selectControl).next());
						break;
					case enter:
						$(selectControl).parents('form').submit();
						break;
				}
			});

			var options = $('<ol>').addClass('hidden plain options');
			$('option', this).each(function() {
				var option = this
				$('<li>').text($(this).text()).click(function(event) { event.stopPropagation();
					selectItem($(option));
					hideActiveDropdown();
				}).appendTo(options);
			});

			function hideActiveDropdown() {
			    if (activeOptions) activeOptions.addClass('hidden');
			}

			function selectItem(item) {
				if (item.length > 0) {
					var currentSelectedItem = $('option:selected', selectControl);
					currentSelectedItem.removeAttr('selected');
					item.attr('selected', 'selected');
					selected.val(item.text());

					var index = $('option', selectControl).index(item);
					var elems = $('li', options).removeClass('selected');
					$(elems.get(index)).addClass('selected');
				}
			}

			$(document).click(hideActiveDropdown);

			selectItem($('option:selected', selectControl));

			var wrapper = $('<div>').addClass('wrapper').append(options).append(selected).click(function(event) {
			    event.stopPropagation();
			    selected.click();
			});
			$(selectControl).addClass('hidden').after(wrapper);
        });
    }

})(jQuery);