How to load a internal page content within div?
You can use jQuery $.load() to load a section of a page:

(function($, Drupal) {
  function loadContent(context) {
    $(context).find("#the_container_div").once("arbitrary-key", function () {
      // $(this) refers to #the_container_div
      $(this).load("http://example.com #container");
    }
  }

  Drupal.behaviors.someArbitraryButUniqueKey = {
    attach: function (context) {
      loadContent(context);
    }
  };
}(jQuery, Drupal));


The function loadContent() loads the content of the #container div at the page example.com into your local container of #the_container_div.