function InitAjaxPro() {
    //console.log('Init Ajax Pro Settings...');
    AjaxPro.onTimeout = AjaxTimeout; // set the on timeout function
    AjaxPro.timeoutPeriod = 60 * 1000 * 20; // set the search timeout to 20 min

}

function AjaxTimeout(r, obj) {
    alert('Request timed out!');
}

Event.observe(window, 'load', InitAjaxPro);