document.getElementsByClassName = function (needle)
{
  var         my_array = document.getElementsByTagName("*");
  var         retvalue = new Array();
  var        i;
  var        j;

  for (i = 0, j = 0; i < my_array.length; i++)
  {
    var c = " " + my_array[i].className + " ";
    if (c.indexOf(" " + needle + " ") != -1)
      retvalue[j++] = my_array[i];
  }
  return retvalue;
}

function addEvent(obj, evType, fn)
{
    if (obj.addEventListener)
    {
        obj.addEventListener(evType, fn, true);
        return true;
    } 
    else if (obj.attachEvent)
    {
        var r = obj.attachEvent("on"+evType, fn);
        return r;
    } 
    else 
    {
        return false;
    }
}


function updateCount()
{
    var counts = document.getElementsByClassName('maxlength');
    var i, count, matches, countHolder;
    
    for (i=0; i<counts.length; i++)
    {
        count = counts[i];  
        matches = count.className.match(/max_([0-9]+)/);
        count.maxVal = RegExp.$1;
        count.holder = document.getElementById(count.id + 'Count');
        if (count.holder)
        {
            count.holder.innerHTML = count.maxVal - count.value.length;
            count.onkeyup = function()
            {
                if (this.value.length > this.maxVal)
                    this.value = this.value.substring(0, this.maxVal);
    
                this.holder.innerHTML = this.maxVal - this.value.length;        
            }
        }
    }   
}

addEvent(window, 'load', updateCount);