First things first with Ajax
The problems with your original (first) question are as follows:


Your callback function expects 2 parameters, but you are providing just one.
You are missing nojs in your url.
You are giving param as a parameter to your callback function, but you wanna % instead/


So it should look like something like this:

  $items['myajax/param/nojs/%'] = array(
    'page callback' =&gt; 'myajax_ajax_callback',
    'page arguments' =&gt; array(2,3), // drupal starts counting from 0 so nojs is 2nd and % is 3th arg
    'access arguments' =&gt; TRUE,
    'access callback' =&gt; TRUE,
    'type' =&gt; MENU_CALLBACK
  );


I hope this will help someone.

P.S.
sorry for my English