function addEvent(obj, type, fn){
    if (obj.addEventListener){
        obj.addEventListener( type, fn, false );
    } else {
        obj["e"+type+fn] = fn;
        obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
        obj.attachEvent( "on"+type, obj[type+fn] );
    }
}

function removeEvent(obj, type, fn){
    if (obj.removeEventListener){
        obj.removeEventListener( type, fn, false );
    } else {
        obj.detachEvent( "on"+type, obj[type+fn] );
        obj[type+fn] = null;
        obj["e"+type+fn] = null;
    }
}