var menupopped=false; 

function nomenu(e){ 
 if(document.layers && e.which>1) return false; 

 if (document.all) { 
  if (event.button>1){ 
    if (popmenu.readyState==4){ 
      popmenu.RemoveAllItems() 
      popmenu.AddItem("","Bitte beachten Sie das Copyright!","",""); 
      popmenu.Popup (event.x,event.y) 
      menupopped=true; 
    }
    else alert("Bitte beachten Sie das Copyright!") 
  } 
  if (event.button==1 && menupopped) { 
     popmenu.RemoveAllItems() 
     popmenu.Popup (event.x,event.y) 
     menupopped=false; 
  }
 } 
 
} 

if (document.layers) {
  document.onmousedown = nomenu;
  document.captureEvents(Event.MOUSEDOWN); 
}

if(document.all) {
  if(parseInt(navigator.appVersion)>=4) {
    document.oncontextmenu=new Function("return false");
  } 
}