// JavaScript Document
var phone_field_length=0;
function TabNext(obj,event,len,next_field) 
{
if (event == "down") 
{
phone_field_length=obj.value.length;
}
else if (event == "up") 
{
if (obj.value.length != phone_field_length) 
{
phone_field_length=obj.value.length;
if (phone_field_length == len) 
{
next_field.focus();
}}}}