code: function resolveUrl(base, url) {
    var value = '';
    if (url.indexOf('://') != -1) {
      // Likely absolute...
      value = url;
    } else {
      // Combine by smashing together and letting the browser figure it out.
      if (url.length && url[0] == '/') {
        // URL is absolute, so strip base to just host.
        var i = url.indexOf('://') + 3;
        i = url.indexOf('/', i);
        if (i != -1) {
          value = base + url;
        } else {
          value = base.substr(0, i) + url;
        }
      } else {
        // URL is relative, so combine with base.
        if (base[base.length] == '/') {
          value = base + '/' + url;
        } else {
          value = base + '/../' + url;
        }
      }
    }
    return value;
  }
docs: Hackily resolves a URL relative to a base.
  @param {string} base Base URL.
  @param {string} url Relative or absolute URL.
  @return {string} Resolved URL.