As we learned in a previous chapter, an asynchronous GlideAjax call is usually the best way to get server-side data that we need for a client-side script. However, GlideAjax is complex and requires creation of both a server-side and client-side script, so in many cases it's just fine to use another asynchronous method (such as GlideRecord) to retrieve data from the server, when we need to access related records in a Client Script, UI Policy script, or other client-side script. However, as we learned earlier in this chapter, it's best to avoid asynchronous calls when dealing with onSubmit Client Scripts; otherwise, the form may submit before the callback function has a chance to be called!