I am not sure what exactly you want. But may be this will help.
var event; // The custom event that will be created
if (document.createEvent) {
event = document.createEvent("HTMLEvents");
event.initEvent("name-of-custom-event", true, true);
} else {
event = document.createEventObject();
event.eventType = "name-of-custom-event";
}
event.eventName = "name-of-custom-event";
if (document.createEvent) {
element.dispatchEvent(event);
} else {
element.fireEvent("on" + event.eventType, event);
}