Conditional ajax loading

i am trying to load some-ajax.php only when specific category
is being viewed… but, no matter what i try or what action / hook
i try to connect the “if($catid = ‘111’) {” condition the ajax
stops working…

The condition is being met but i guess i got things mixed up
with the order of load..?

in my functions.php i am testing for the category

global $post;
$category = get_the_category($post->ID);
$catID = $category[0]->term_id;
if($catID == '111') {
 include(TEMPLATEPATH.'/ajaxLoops/tools/ajax-example.php');
}

Then inside “ajax-example.php” i have this code (just example):

wp_enqueue_script( 'ajax-site-screenshot', get_stylesheet_directory_uri().'/ajaxLoops/tools/ajax-get_site_screenshot.js', array('jquery'), 1.0 ); // jQuery will be included automatically
wp_localize_script( 'ajax-site-screenshot', 'ajax_object', array( 'ajaxurl' => admin_url( 'admin-ajax.php' ) ) ); // setting ajaxurl

add_action( 'wp_ajax_action_site_screenshot', 'ajax_site_screenshot' ); // ajax for logged in users
add_action( 'wp_ajax_nopriv_action_site_screenshot', 'ajax_site_screenshot' ); // ajax for logged in users
function ajax_site_screenshot() {
	$w150 = '
	<div class="fullb">
	<img src="http://s.wordpress.com/mshots/v1/' . urlencode($site_url) . '?w=150"/>
	</div>';

	echo '<div id="w150">'.$w150.'</div>';

	die(); // stop executing script
}

Could anyone help / guide / refrence me? i search for a similer
problem or question but could not find any data on this.

My theme has 20-30 ajax files and i dont want to load each and
every one of them in every page when some are only used in specific category…

i would love for an example since i am a loss..

Thanks.
Sagive