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 getLoadingHtml() {
    var imgSrc = getContextPath()+"/images/loading.gif";
    return '<div class="jQueryAjaxLoading"><img src="'+imgSrc+'" />.</div>';
}

function getErrorHtml() {
    var html =  '<div class="message_error">Could not perform operation.</div>';
    return html;
}