var ut  = new ActiveXObject("CAPICOM.Utilities"); 
var text = '123';//подписываемые данные
var dataInBase64 = ut.Base64Encode(text)
var signedMessage = SignCreate(dataInBase64);
var verifyResult = Verify(signedMessage, dataInBase64);
if (verifyResult) {
    alert("Signature verified");
}
...
...
function SignCreate(dataToSign) {
      SignedData = new ActiveXObject("CAPICOM.SignedData");
      Signer = new ActiveXObject("CAPICOM.Signer");
      var TimeAttribute = new ActiveXObject("CAPICOM.Attribute");
      if (txtCertificate.hash != "") {
        try {
          Signer.Certificate = FindCertificateByHash(txtCertificate.hash);
            var Today = new Date();
            TimeAttribute.Name = CAPICOM_AUTHENTICATED_ATTRIBUTE_SIGNING_TIME;
            TimeAttribute.Value = Today.getVarDate();
            Today = null;
            Signer.AuthenticatedAttributes.Add(TimeAttribute);
            Signer.Options = 1;
			SignedData.Content = dataToSign;			
			return SignedData.Sign(Signer, true, CAPICOM_ENCODE_BASE64);			
        } catch (e) {
          if (e.number != CAPICOM_E_CANCELLED) {
            alert("При попытке подписи произошла ошибка!\n" + e.description);
            return false;
          }
        }
      } else {
        alert("Ни один сертификат не выбран!");
      }
    }
	
	function Verify(sSignedMessage, dataToVerify) {
        try {
			SignedData.Content = dataToVerify; 
			SignedData.Verify(sSignedMessage, true, CAPICOM_VERIFY_SIGNATURE_AND_CERTIFICATE);
			return true;
		} catch (e) {
			alert("При проверке подписи произошла ошибка!\n" + e.description); 
			return false;
		}
    }