Is there a way to find the vCenter reference for a linux server in ServiceNow with automation using a Catalog Client script?

I’m developing a new ServiceNow catalog item that takes an input of a Linux Server name and has a requirement of locating the associated vCenter reference for it and adding it to a field on the catalog item to make it available for a back end flow. I can find the vCenter reference manually with query builder, connecting the cmdb_ci_linux_server & cmdb_ci_esx_server tables (cmdb classes), but haven’t had success yet working with the Catalog Client script GlideRecord approach. Any thoughts, ideas, or examples on how to do this?

1)//Testing in Background Scripts, I can find the valid sys_id for a known linux server
var test1svr = new GlideRecord('cmdb_ci_linux_server');
test1svr.addQuery('name', 'example_server_name');
if (  {
    //found, nothing further needed in this leg


//return test1svr.sys_id

2)//Testing in Background Scripts, interim step of locating the associated ESX server for a given linux
//server ... with the Virtualized by::Virtualizes relationship type ... querying the Client
//Relationship table
var rel = new GlideRecord('cmdb_rel_ci');
rel.addQuery('parent', 'example linux server sys id');
rel.addQuery('type', 'example sys id for Virtualized by::Virtualizes type');
if ( {
    //found, nothing further needed in this leg


//return rel.sys_id

Successful results ... I verified the sys_id's & names were the ones I was expecting.  The parent in     this case is the linux server and the child is the associated ESX server for the Virtualized by::Virtualizes relationship type. 

3) I tried the interim step of finding the associated ESX server using an onChange Catalog Client script, but this doesn't seem to be the right approach, since it's ignoring me ... I keep getting my "testing outside the if" .  My interim goal is to find the associated ESX Server, populate a variable with the value  and use that to find the vCenter Reference on the configuration tab of the associated ESX Server.  

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {

    //Locating the associated ESX server
    // var rel1 = new GlideRecord('cmdb_rel_ci');
    // rel1.addQuery('parent', u_server);
    // rel1.addQuery('type', 'example sys id for type');
    // rel1.query();
    // if ( {
    //found, nothing further needed in this leg

    // g_form.setValue("u_associated_esx_server", "testing a hit");

    // }
    // var rel = new GlideRecord('cmdb_rel_ci');
    // var test1 = 'example sys id for linux server';
    // rel.addQuery('parent', test1);
    // rel.addQuery('type', 'example sys id for type');
    // rel.query();
    // if ( {
    //     //found, nothing further needed in this leg

    //     g_form.setValue("u_associated_esx_server", "testing ... inside if");
    // }

    g_form.setValue("u_associated_esx_server", "testing ... outside if");