// Auto tab function
var isNN = (navigator.appName.indexOf("Netscape")!=-1);

function tabNext(input,len,e,next_id){
  var keyCode = (isNN) ? e.which : e.keyCode;
  var filter = (isNN) ? [0,8,9] : [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);
    document.getElementById(next_id).focus();
  }

  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].name == input.name)
      index = i;
    else
      i++;
    return index;
  }

  return true;
}