function click() {
if (event.button==2) 
   {
   alert ('Direitos Reservados !!! Niposoft Sistemas')
   }
}
document.onmousedown=click 

function clique (mensagem) 
{
  alert (mensagem);
}

function centerWindow(nomepagina) 
{
if (document.all)
var xMax = screen.width, yMax = screen.height;
else
if (document.layers)
var xMax = window.outerWidth, yMax = window.outerHeight;
else
var xMax = 800, yMax=600;
var xOffset = (xMax - 200)/2, yOffset = (yMax - 200)/2;
window.open(nomepagina,'windowbis','width=640,height=480,scrollbars=yes,screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');
}


<!-- 
/*Background fade by Dave Methvin, Windows Magazine
May be used/modified if credit line is retained*/
function BgFade(red1, grn1, blu1, red2, grn2, blu2, steps) 
{
  sred = red1; sgrn = grn1; sblu = blu1; 
  ered = red2; egrn = grn2; eblu = blu2; 
  inc = steps; 
  step = 0; 
  var bName = navigator.appName;
  if (bName == 'Microsoft Internet Explorer')
      RunFader();
}
function RunFader() 
{
  var epct = step/inc; 
  var spct = 1 - epct; 
  document.bgColor =
  Math.floor(sred * spct + ered * epct)*256*256 +
  Math.floor(sgrn * spct + egrn * epct)*256 +
  Math.floor(sblu * spct + eblu * epct); 
  if ( step < inc ) 
  {
       setTimeout('RunFader()',50); 
  }
  step++;
}
BgFade(0x00,0x00,0x00, 0xFF,0xFF,0xFF,10); 
//-->


nova=null;
function imagem_h(nome) 
{
if ( navigator.appName == "Netscape" ) 
   {
   nova=window.open(nome,"title","toolbar=0,location=0,directories=0,status=no,menubar=no,scrollbars=auto,resizable=yes,copyhistory=yes,width=640,height=480");
   nova.focus();
   }
else {
   nova=window.open(nome,"title","toolbar=0,location=0,directories=0,status=no,menubar=no,scrollbars=auto,resizable=yes,copyhistory=yes,width=640,height=480");
   }
}


function imagem_v(nome,largura,altura) {
if ( navigator.appName == "Netscape" ) {
   nova=window.open(nome,"title","toolbar=0,location=0,directories=0,status=no,menubar=no,scrollbars=auto,resizable=no,copyhistory=yes,width=260,height=400");
   nova.focus();}
else {
   nova=window.open(nome,"title","toolbar=0,location=0,directories=0,status=no,menubar=no,scrollbars=auto,resizable=no,copyhistory=yes,width=260,height=400");}
}