redirector.js

// example usage:
//  <script type="text/javascript" src="redirector.js"></script>
//
// <script type="text/javascript">
//   (function (global) { 
//     redir = global.Redirector;
//
//     redir.width = 1400; // optional
//     redir.base_url = "http://example.com";
//     redir.redirect();
//   }) (window);
// </script>
//

(function (global) {
  'strict mode';

  global.Redirector = global.Redirector || {
    width: 700,
    noredirect_param: 'noredirect',

    stripped_url: function () {
      return this.base_url.replace(/\/$/, '');
    },

    path: function () {
      var a = document.createElement('a')
      a.href = global.location;

      return a.pathname + a.search + a.hash;
    },

    redirect_to: function () {
      return this.stripped_url() + this.path();
    },

    noredirect: function () {
      return new RegExp(this.noredirect_param, 'i').test(global.location);
    },

    redirect: function () {
      if (this.noredirect()) return;

      if (screen.width < this.width) {
        global.location = this.redirect_to();
      }
    }
  };
}) (window);