function autoTab(input,len)
{	
	var e = window.event;
	var valid = "0123456789";
	var strPass = input.value;
	var strLength = input.length;
	var lchar = input.value.charAt((strLength) - 1);
	var temp;
	for (var i = 0; i < input.value.length; i++)
	{
		temp = "" + input.value.substring(i, i+1);
		if (valid.indexOf(temp) == "-1")
		{
			var ch = input.value.substring(0, (strLength) - 1);
			input.value = ch;
		}
	}

  var keyCode = e.keyCode; 
  var filter = [0,8,9,16,17,18,37,38,39,40,46];
  if(input.value.length >= len && !containsElement(filter,keyCode))
  {
    input.value = input.value.slice(0,len);
	if(input.form[(getIndex(input)+1)%input.form.length].type != "hidden")
	{
		input.form[(getIndex(input)+1)%input.form.length].focus();
	}
	
	if(	   input.form[(getIndex(input)+1)%input.form.length].type.indexOf("text") >= 0
		|| input.form[(getIndex(input)+1)%input.form.length].type == "password"
		|| input.form[(getIndex(input)+1)%input.form.length].type == "file")
	{
    	input.form[(getIndex(input)+1)%input.form.length].select();
	}
  }
  
  function containsElement(arr, ele)
  {
    var found = false, index = 0;
    while(!found && index < arr.length)
      if(arr[index]==ele)
        found = true;
      else
        index++;
    return found;
  }
  
  function getIndex(input)
  {
    var index = -1, i = 0, found = false;
    while (i < input.form.length && index==-1)
      if (input.form[i] == input)index = i;
      else i++;
    return index;
  }
  return true;
}