switch window.onerror with addeventlistener?

[dxe4]

allows other libraries to use .onerror as well.
i think this is what jquery does:

    if ( window.addEventListener ) {
        window.addEventListener(eventname, func, false);
    } else {
        window.attachEvent(eventname, func);  // IE <=8 (not sure if event name is the same)
    }