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