function clickIE4()
{
if (event.button==2)
  {return false;}
}

function clickNS4(e)
{
if (document.layers||document.getElementById&&!document.all)
  {if (e.which==2||e.which==3){return false;}
  }
}
if (document.layers){
document.captureEvents(Event.MOUSEDOWN);
document.onmousedown=clickNS4;
}
else if (document.all&&!document.getElementById){
document.onmousedown=clickIE4;
}
document.oncontextmenu=new Function("return false")