var Common = {
  includes : ['rollover', 'menufolder'],
  path : '/js/',

  require: function() {
    for(var i=0; i<this.includes.length; i++) {
      document.write('<script type="text/javascript" src="' + this.path + this.includes[i] + '.js"></script>');
    }
  }
}

Common.require();