var Ajax;
if (Ajax && (Ajax != null)) {
    Ajax.Responders.register({
    onCreate: function() {
        if($('spinner') && Ajax.activeRequestCount>0)
        Effect.Appear('spinner',{duration:0.5,queue:'end'});
    },
    onComplete: function() {
        if($('spinner') && Ajax.activeRequestCount==0)
        Effect.Fade('spinner',{duration:0.5,queue:'end'});
    }
    });
}

// jQuery AJAX utils.

function loadingIndication() {
    return jQuery('#jQueryAjaxLoading').clone();
}

function errorIndication(jqXHR, textStatus, errorThrown) {
    return jQuery('#jQueryAjaxDefaultError').clone().append('Status:'+jqXHR.status+', '+textStatus+'.');
}

// Apply updates to multiple page elements.
// @json JSON response object from an ajax request.
// @json.updates Array of element updates to apply.
// @element.mode The update mode: execute or replace, prepend, append.
// @element.script Script to execute, if execute mode.
// @element.target jQuery target selector, if update mode.
// @element.content Content to update target with, if update mode.
function applyElementUpdates(json) {
    var updates;
    var script;

    if(json.updates) {
        updates = json.updates;
        var element;
        var scripts = new Array();

        for(element in updates) {
            element = updates[element];

            switch(element.mode) {
                case 'execute':
                    scripts.push(element.script);
                    break;
                case 'replace':
                    jQuery(element.target).html(element.content);
                    break;
                case 'prepend':
                    jQuery(element.target).prepend(element.content);
                    break;
                case 'append':
                    jQuery(element.target).append(element.content);
                    break;
            }
        }

        // Run scripts.
        for(script in scripts) {
            script = scripts[script];
            eval(script);
        }

    } // if(json.updates)
} // applyElementUpdates