if (document.layers){
    window.captureEvents(Event.MOUSEDOWN | Event.MOUSEUP)
    window.onmousedown=rightclick;
    window.onmouseup=rightclick;
    
    function rightclick(e) {
    if (e.which == 3) {
    
    return false; 
    }
    else {
        return true; 
        }
    }
}

if (document.all){
    function click() {
    if (event.button==2) {
    alert('copyrights by mtb-biking')
    }
    
    if (event.button==3) {
    alert('copyrights by mtb-biking')
}
    }
    document.onmousedown=click
}