<form name="F1" method="POST" action="http://russianpost.ru/rp/servise/ru/home/postuslug/trackingpo" target="_blank">


<script type="text/javascript" language="Javascript">            
            
    
  
function CheckInputCode()            
{            
var validcode= document.getElementById("validcode");            
var BarCode= document.getElementById("BarCode");            
var searchsign = document.getElementById("searchsign");            
var lblVldCdeErrMsg = document.getElementById("lblVldCdeErrMsg");            
var lblBrcdErrMsg= document.getElementById("lblBrcdErrMsg");            
            
if(BarCode.value == "")            
{            
lblBrcdErrMsg.innerHTML  = "Не введён почтовый идентификатор!";            
//lblVldCdeErrMsg.innerHTML = "";            
return;            
}            
            
var checkPatern = /\d{14}/;            
if(!checkPatern.test(BarCode.value))            
{            
   var chechInternationalWorld = /[a-z]{2}\d{9}[a-z]{2}$/i;            
   if(!chechInternationalWorld.test(BarCode.value))            
    {            
      lblBrcdErrMsg.innerHTML  = "Трек "+BarCode.value+ " Не существует";    

    
       return;            
}            
}            
            
            
if(BarCode.value != "")            
{            
  searchsign.value="1";            
  document.forms[0].submit();            
}            
}            
<!----></script>



<input type="text" id="BarCode" name="BarCode" size="14" maxlength="14" value=""></input>
<DIV id="lblBrcdErrMsg" style="COLOR: red; DISPLAY: inline; WIDTH: 50%; HEIGHT: 15px" ms_positioning="FlowLayout" />
<input type="hidden" id="searchsign" name="searchsign" />
<input type="button" name="searchbarcode" onclick="CheckInputCode();" value="Search"></input>