JQuery :: Showing Form After Button Click And Then Making Some Scripts?

this is my first visit here so I would like to introduce myself.I`m Krystian :)I`m a newbie in Ajax, jQuery.

I've created a php file which contains form ( form.php ). This file is inserted after button click in index.php. In index.php I`m including jQuery library. My problem is that: when I`m trying the code below, just for test. This is not working. JS console doesn`t show any errors. Why such a simple code is not visible with form? When this example will work then I would like to code something much more difficult on this form. Best Regards Krystian. p.s. When I`ve created form directly in index.php alert occurs.$("select#numberPers").change(function(){ alert('you have changed the select option field');