function blockError(){return true;}
window.onerror = blockError;

function disableselect(e)
{
   return false
}

function reEnable()
{
   return true
}

//if IE4+
document.onselectstart=new Function ("return false")

//if NS6
if (window.sidebar)
{
   document.onmousedown=disableselect
	document.onclick=reEnable
}

function click(mouse)
{
  if (document.all)
  {
     if (event.button==2||event.button==3)
     {
        alert(mensagem);
        return false;
     }
  }
  if (document.layers)
  {
     if (mouse.which == 3)
     {
        alert(mensagem);
        return false;
     }
  }
}
document.onmousedown=click;
document.onkeydown=keypressed;