var message = 'this page\noff limit!\n';

if (document.layers) {
    captureEvents(Event.MOUSEDOWN);
    onmousedown = myMouseDown;
} else if (document.all)
    document.onmousedown = myMouseDown;
    document.onmouseup = myMouseDown;

    function myMouseDown(e){
        if (document.layers && e.which >= 2) {
            alert(message);
            return false;
        } else if (document.all && event.button >= 2) {
            if(event.type == 'mouseup')
            document.body.createTextRange().select();
            alert(message);
            return false;
        }
    }