How to load a plugin when doing an Ajax call? [duplicate]

You are not using ajax right. Why are you adding your ajax callback function to the init action? You need to read http://codex.wordpress.org/AJAX_in_Plugins

Attach your ajax callback function to wp_ajax_your_defined_action like this:

add_action( 'wp_ajax_your_defined_action', 'your_callbck_function' );

For this to work you have to use wp-admin/admin-ajax.php as your ajax url and you have to post your_defined_action to action.

            $.ajax({
                type: 'POST',
                url: ajaxurl, //This is defined only on admin side
                data: {
                    action: 'your_defined_action',
                    some_var: 'Some Var Content'
                },
                success: function (response) {
                    alert(response);
                }
            });