A simple router that registers callbacks for popstate events.

router.amd.js

define(['underscore'], function(_) {

	return new function() {
	  
		var self = this;
		var routes = [];
		var catchAllCallback = null;

		this.addRoute = function(pattern, callback) {
			routes.push({pattern: pattern, callback: callback});
		};

		this.catchAll = function(callback) {
			catchAllCallback = callback;
		};

		this.route = function() {
			var path = window.location.hash.substring(1);

			var found = false;

			_.each(routes, function(route) {
				var matches = path.match(route.pattern);
				if (matches) {
					if (route.callback) {
						route.callback.call(null, matches);
						found = true;
					}
				}
			});

			if (!found && catchAllCallback) 
				catchAllCallback.call(null);
		};

		this.go = function(path) {
			var currentURL = window.location.href;

			currentURL = currentURL.replace(/#.*/, '') + '#' + path;
			window.history.pushState(null, null, currentURL);
			this.route();
		};

		window.onpopstate = this.route;
    
	};
	
});