var messages = {"checkUserTrue": "Введенное имя пользователя уже занято",
                "checkUserFalse": "Имя пользователя [% user_name %] свободно",
                "checkUserUndef": "Пожалуйста введите имя пользователя"};



function checkUser()
{
  window.document.getElementById("checkButton").disabled = true;
  var userName = window.document.getElementById("t1").value;
  sendRequest("userStatus", 
              "GET", 
              "/register/", 
              {"a": 3, "un": userName}, 
              printUserStatus, 
              false);
}



function printUserStatus(requestObj, parentObj)
{
  if (requestObj.readyState == 4)
    {
      removeAllChild(parentObj);

      var userName = window.document.getElementById("t1").value;
      var br;
      var span;
      var text;

      if (requestObj.status == 200)
        {
          var fstatus = requestObj.responseText
          if (fstatus == "0")
            {
              span = window.document.createElement("span");
              span.className = "ferror";
              text = window.document.createTextNode(messages.checkUserUndef);
              span.appendChild(text);
              parentObj.appendChild(span);
            }
          else if (fstatus == "1")
            {
              span = window.document.createElement("span");
              span.className = "field-info";
              var msg_before = messages.checkUserFalse.substring(0, messages.checkUserFalse.indexOf("[%"));
              var msg_after = messages.checkUserFalse.substring(messages.checkUserFalse.indexOf("%]") + 2, messages.checkUserFalse.length);
              text = window.document.createTextNode(msg_before);
              span.appendChild(text);
              var strong = window.document.createElement("strong");
              text = window.document.createTextNode(userName);
              strong.appendChild(text);
              span.appendChild(strong);
              text = window.document.createTextNode(msg_after);
              span.appendChild(text);
              parentObj.appendChild(span);
            }
          else if (fstatus == "2")
            {
              span = window.document.createElement("span");
              span.className = "ferror";
              text = window.document.createTextNode(messages.checkUserTrue);
              span.appendChild(text);
              parentObj.appendChild(span);
            }
        }
      window.document.getElementById("checkButton").disabled = false;
    }
}



function button_on(inputObj)
{
  checkButton = window.document.getElementById("checkButton");
  if (inputObj.value && (inputObj.value != ""))
    {
      checkButton.disabled = false;
    }
  else
    {
      checkButton.disabled = true;
    }
}