myModalBootstrap.js

 var MyModal = function() {  
    var $elem, options, Modal;
    
    Modal = $.fn.modal.Constructor;
    $elem = $('#myModal'); 
    options = $.extend({}, Modal.DEFAULTS, $elem.data());  
    
    // call father constructor
    Modal.call(this, $elem, options);  
  }
  
  MyModal.prototype = $.fn.modal.Constructor.prototype;
  
  var myModal = new MyModal({});
  
  myModal.show();