What are the different ways to call client side from server side and vice versa?

[tiagomacul]

With Now Assist, the way client–server interactions are handled shifts slightly compared to classic GlideAjax/g_scratchpad.

🔄 Client → Server in Now Assist

• The Now Assist client component (for example, in Agent Workspace or Employee Center) .

• Instead, it calls GenAI Providers or GenAI Actions which are defined server-side.

• Behind the scenes, ServiceNow uses Data Brokers

• You can still fall back on GlideAjax or REST APIs, but Now Assist favors the Action Framework for structured server calls.

🔄 Server → Client in Now Assist

• Responses from the server are not raw field values or XML like in GlideAjax.

• The server (through Actions, GenAI Providers, or Scripted APIs) returns structured JSON, which Now Assist renders into the conversation or workspace UI.

• You can enrich the response with UI Actions (e.g., “Update Incident Priority”), which then invoke client-side components automatically.

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✅ Key Difference vs. Classic Model

• Classic client–server: developer explicitly wires GlideAjax or g_scratchpad.

• Now Assist: developer defines Actions/Providers, and the platform handles the client–server call lifecycle.

• Instead of thinking in terms of “call this Script Include”, you think in terms of “expose this action to the AI”.

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👉 So when we talk about client ↔ server in Now Assist, the main difference is abstraction:

You still have server-side scripts and client-side rendering, but Now Assist routes everything through its Action & Provider framework rather than direct GlideAjax.

• GlideRecord & GlideAjax: Client-Side Vs. Server-Side.
• ServiceNow Client-Side vs Server-Side (video).
• ServiceNow Code and Beyond: Client-Side vs Server-Side Scripting in ServiceNow.
• Client & Server Code in One UI Action.
• Client and Server-side Programming.
• What is Client-Side and Server-Side Scripting in ServiceNow.
  
  

[kaushal_snow]

Hi @SahanaR ,

• GlideAjax → Script Include: Client side uses GlideAjax to asynchronously call server side logic via Script Include...
• getReference: Client side can fetch full related record details without a GlideRecord query....
• g_scratchpad (via Display Business Rule): Preloads server side data for client-side access when the form loads....
• UI Action (combined): UI Actions can include both client and server side code, toggled via the Client checkbox....
• Portal Widgets (c.server.get): Within Service Portal, client controllers call c.server.get, handled by corresponding server scripts....

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[Nikhil Bajaj9]

Hi @SahanaR ,

Calling Server-Side from Client-Side:

• GlideAjax: A client script uses GlideAjax to call a server-side Script Include, which then performs server-side operations (e.g., database queries, calculations) and returns data to the client. This allows for dynamic updates without a full page refresh.
• getReference() (with callback): We have a client side method getreference() which can be used for fetching data from a referenced record. Recommendation is to call use it with callback function which will make it asynchronous and prevent UI blocking. Withotut callback method, it is not recommended.

Calling Client-Side from Server-Side:

• g_scratchpad (via Display Business Rule): This is used to pass data from the server to the client when a form loads. A Display Business Rule can populate the g_scratchpad object with server-side data, which can then be accessed by client scripts (e.g., onLoad client scripts).But remember it will be only when form is loaded not after that (Dynamic data fetching – Glideajax can be used to get dynamic data)

• UI Actions (Client-side and Server-side Scripting in one):

A UI Action can be configured to run both client-side and server-side code. The "Client" checkbox determines if client-side code is executed. Within the script, you can use if (typeof window == 'undefined') to differentiate between server-side and client-side execution contexts.

Further details for 4th point can be seen here:-

https://www.servicenow.com/community/community-central-forum/how-do-you-run-the-client-side-and-the-...

and the last method is - through portal widgets.