function rightbuttondisable() {
  document.oncontextmenu = function(){return false}
  if(document.layers) {
    window.captureEvents(Event.MOUSEDOWN);
    window.onmousedown = function(e){
        if(e.target==document)return false;
    }
  } else {
    document.onmousedown = function(){return false}
  }

  document.oncontextmenu = function(){return false}

  if(document.layers) {
    window.captureEvents(Event.MOUSEDOWN);
    window.onmousedown = function(e){
        if(e.target==document)return false;
    }
  } else {
    document.onmousedown = function(){return false}
  }
}