Add Drupal Forms using AJAX ...

Something very easy to do in drupal is adding form object to the content of your page without doing a page refresh.  I needed to add functionality so that an application form was displayed to a user when they clicked the Apply link.

Using JQuery we can “intercept” a client click of a link.  Add a .js file to which ever module you are editing, and add the following:

     if (Drupal.jsEnabled) { 

      $(document).ready(function () {
        $(’a.apply-link’).click(function () {

          var submitApplication = function(data) {
            $(’div.apply-link’).html(data.html);
          }
        $.ajax({
          type: ‘POST’,
          url: this.href,
          dataType: ‘json’,
          success: submitApplication,
          data: ‘js=1′
        });
        return false;
      });
      });
    }

So when a link with a class “submit-application” is clicked an ajax/json call is made to the url.  Now make sure the js is included somewhere in your module code by using drupal_add_js().
Now all we have to do is make sure the page renders as json if an ajax call is made.  Add this  code just before the _page exits (but not after the exit(); !).

     if (!empty($_POST[js])) {
        $html = drupal_get_form(’job_posting_application_form’, array($node->nid, $node->title, $node->job_posting_email));
        drupal_json(array(
        ‘html’ =>  $html
        )
        );

Your link should be replaced with the form.
If you want to add a little bit of animation use the jQuery animation options.  Instead of just replacing the link, make it fade in:

    $(’div.apply-link’).hide();
    $(’div.apply-link’).html(data.html);
    $(’div.apply-link’).fadeIn();

 Original Source:
http://jarchowk.wordpress.com