How to read a custom list based on the data of a drop down field?

Hi All,

We wrote a script to fetch all the fields from a transaction record.We successfully got all the fields , among all the fields i want to use only the select fields. Here i'm getting the standard lists but i'm unable to fetch the custom list for a particular select fields. Instead of getting custom lists i'm getting only the fields internal id. Can any one help me out of this.Below is the snippet i used.

var form = nlapiLoadRecord('noninventoryitem',42);
var allfields = form.getAllFields();
for(var x=0; x<allfields.length; x++)
  {
var fld = allfields[x];
var fld_grp = form.getField(fld);