var MaxLengthLock = false;

function MaxLengthCount(fieldObj,fieldMaxLength)
{
  if (!MaxLengthLock)
  {
    MaxLengthLock = true;
    if (fieldObj.value.length > fieldMaxLength)
    {
      alert("Text je delší než " + fieldMaxLength + " znaků!");
      fieldObj.value = fieldObj.value.substring(0,fieldMaxLength);
    }
    var percentage = parseInt(100 - (( fieldMaxLength - fieldObj.value.length) * 100)/fieldMaxLength);
    document.getElementById(fieldObj.id + "_bar").style.width = parseInt((parseInt(fieldObj.offsetWidth)*percentage)/100)+"px";
    MaxLengthLock = false;
  }
}