wordpress ajax

functions.php

<?php

// wp-admin/admin-ajax.php?action=getspeaker&a=b&c=d...

add_action( 'wp_ajax_nopriv_getspeaker', 'getspeaker' );
add_action( 'wp_ajax_getspeaker', 'getspeaker' );

function getspeaker(){
	$offset = $_REQUEST['offset'];
	
	$already = explode(",",$_REQUEST['already']);
	$retID = -1;
	do {
		$query = new WP_Query( 'post_type=speaker&category_name=featured&posts_per_page=1&orderby=modified&offset='.$offset );
		$result = null;
		while ( $query->have_posts() ) {
			$query->the_post();
			$result->link = get_permalink();
			$image = array_shift(get_children('post_type=attachment&post_mime_type=image&post_parent='.get_the_ID() )); 
			$result->source = $image->guid;
			$custom = get_post_custom();
			$result->title = get_the_title();
			$result->description = $custom['title'][0];
			$result->id = $retID = get_the_ID();
		}
		$offset++;
	} while(in_array($retID, $already));
	echo json_encode($result);
	exit();
}