jQuery.slideShow.js

(function($) {
    $.fn.slideShow = function() {
		var prefix = "slide";
		var l = location.protocol + "//" + location.hostname + location.pathname;
		var pages = this.length;
		var fragment_pattern = RegExp("#" + prefix + "(\\d+)");
		if(! fragment_pattern.test(location.hash)) {
			location.href = l + "#" + prefix + "1"; // don't reload page with Firefox;
		}
		var pageNumber = function() {
			var fragment;
			return (fragment = location.hash) != "" ?
				fragment.replace("#" + prefix, "") - 0 :
				1;
		};
		var previousPage = function() {
			var ppn = pageNumber() - 1;
			if (ppn >= 1) {
				location.href = l + "#" + prefix + ppn;
			}
		};
		var nextPage = function() {
			var npn = pageNumber() + 1;
			if (npn <= pages) {
				location.href = l + "#" + prefix + npn;
			}
		};
		$(document).keyup(function(e) {
			switch (e.keyCode) {
				case 38: // Up
					previousPage();
					return;
				case  40: //Down
					nextPage();
					return;
				default:
					return;
			}
		});
		return this.each(function(i) {
			var page = $(this);
				page.attr("id", prefix + (i+1)).addClass(prefix);
			
		});
	};
})(jQuery);