WordPress AJAX JSON

ajax-enqueue-core-json.php

// embed the javascript file that makes the AJAX request
// don't forget to specify 'json2' as the dependency
wp_enqueue_script( 'my-ajax-request', plugin_dir_url( __FILE__ ) . 'js/ajax.js', array( 'jquery', 'json2' ) );

ajax-jason-own-jquery.php

wp_enqueue_script( 'json2' );
// don't forget to specify dependency
wp_enqueue_script( 'myjQuery', plugin_dir_url( __FILE__ ) . 'js/jquery.1.4.2.js', array( 'json2' ) );

ajax-jason.php

wp_enqueue_script( 'json2' );

ajax-json.js

jQuery.post( MyAjax.ajaxurl, { action : 'myajax-submit' },
	function( jsonString ) {
		// use JSON parser on the response string instead of
		// specifying the response type as json
		var object = JSON.parse(jsonString);
	}
);