window.book = window.book|| {};

window.book = {
  control: function() {
    var check_is_ready = 'check_is_ready';
    if(check_is_ready == 'check_is_ready') {
      this.startbook = function() {
        var bookMain = new book.main();
        bookMain.method();
        return;
      };
    };
  },

  main: function() {
    var index =0;
    this.method = function() {
      index++;
      if (index <= 500){
        book.main.method();//  <-- this wrong
        // the error which I get :Uncaught TypeError: Object function () {
        alert (index);
      }
    };
  };
}

$(function() {
    var control = new book.control();
    control.startbook();
});