function addEvent(obj, evType, fn, useCapture){
    if (obj.addEventListener){
        obj.addEventListener(evType, fn, useCapture);
        return true;
    } else if (obj.attachEvent){
        var r = obj.attachEvent("on"+evType, fn);
        return r;
    } else {
        obj["on"+ evType] = obj["e"+evType+fn];
    }
}

function rmEvent(obj, evType, fn, useCapture){
    if (obj.removeEventListener){
        obj.removeEventListener(evType, fn, useCapture);
        return true;
    } else if (obj.detachEvent){
        var r = obj.detachEvent("on"+evType, fn);
        return r;
    } else {
        obj["on"+ evType] = null;
    }
}