JavaScript URL-based menu activation code

menu_items_and_activation_patterns.js

// USAGE: This code parses the browser's URL and displays either the matching menu section or an error if one couldn't be found.

// Associative array of menu items to activate and the regular expression
// fragments that activate them:
var menu_items_and_activation_patterns = { 
  "about":     "about",
  "attend":    "(attend|register)",
  "blog":      "(blog|archive)",
  "schedule":  "events/.+?/schedule",
  "sessions":  "events/.+?/sessions",
  "proposals": "events/.+?/proposals",
  "speakers":  "events/.+?/speakers",
  "sponsors":  "sponsors"
}

var pathname = window.location.pathname;
// Uncomment line below to set a specific pathname for development:
// var pathname = "/events/2009/speakers";
var menu_item_matched = null;
for (var menu_item in menu_items_and_activation_patterns) {
  var pattern = menu_items_and_activation_patterns[menu_item];
  var re = new RegExp("^/" + pattern + "(?:/.*)?$");
  if (pathname.match(re)) {
    menu_item_matched = menu_item;
    break;
  }
}
if (menu_item_matched) {
    alert("Matched menu item: " + menu_item);
} else {
    alert("No match for pathname: " + pathname);
}