Call Javascript onchange event by programmatically changing textbox value

This is an old question, and I’m not sure if it will help, but I’ve been able to programatically fire an event using:

if (document.createEvent && ctrl.dispatchEvent) {
    var evt = document.createEvent("HTMLEvents");
    evt.initEvent("change", true, true);
    ctrl.dispatchEvent(evt); // for DOM-compliant browsers
} else if (ctrl.fireEvent) {
    ctrl.fireEvent("onchange"); // for IE
}