hi @sanketkhot7 ,
Let’s understand GlideAjax and Script Includes with a practical example.
1. What is GlideAjax?
GlideAjax allows a Client Script to call a server-side Script Include and retrieve data without reloading the form.
For example, when you select a Caller on an Incident form, you want to retrieve their department automatically. Instead of reloading the form, you can use GlideAjax to get the department from the server.
2. What is a Script Include?
A Script Include is a reusable server-side JavaScript component. You can write logic once and call it from Business Rules, other server-side scripts, or Client Scripts through GlideAjax when configured as client-callable.
Common types include:
-
On-demand/Classless: A function or script that can be called directly, depending on its configuration.
-
Class-based: A reusable class created using Class.create().
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Client-callable: A Script Include that can receive requests from client-side GlideAjax.
3. What is AbstractAjaxProcessor?
AbstractAjaxProcessor is the base class used by client-callable Script Includes to handle GlideAjax requests.
When extending it, you can retrieve client parameters using this.getParameter() and return a response to the Client Script.
4. What are addParam(), getXMLAnswer(), and callbacks?
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addParam() sends a parameter to the server.
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getXMLAnswer() sends the request asynchronously and provides the returned answer to a callback function.
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getXML() also sends an asynchronous request, but the callback receives the XML response object.
A callback function runs when the server response becomes available. This allows the form to remain responsive while the request is processed.
5. Practical example: Get the Caller’s department
Step 1: Create a Script Include
Example:
var CallerDetailsAjax = Class.create();
CallerDetailsAjax.prototype = Object.extendsObject(
global.AbstractAjaxProcessor, {
getDepartment: function() {
var callerId = this.getParameter('sysparm_caller_id');
if (!callerId)
return '';
var user = new GlideRecord('sys_user');
if (user.get(callerId))
return user.getValue('department') || '';
return '';
},
type: 'CallerDetailsAjax'
}
);
Step 2: Create an onChange Client Script
-
Table: Incident
-
Field: Caller
-
Type: onChange
function onChange(control, oldValue, newValue, isLoading) {
if (isLoading || !newValue)
return;
var ga = new GlideAjax('CallerDetailsAjax');
ga.addParam('sysparm_name', 'getDepartment');
ga.addParam('sysparm_caller_id', newValue);
ga.getXMLAnswer(function(answer) {
if (answer) {
g_form.setValue('u_caller_department', answer);
} else {
g_form.clearValue('u_caller_department');
}
});
}
Replace u_caller_department with the actual field name on your Incident form.
6. How does the request work?
-
The user changes the Caller field.
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The Client Script creates a GlideAjax request.
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sysparm_name tells ServiceNow which Script Include method to execute.
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sysparm_caller_id sends the selected user's sys_id.
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The Script Include retrieves the department.
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The server returns the department's sys_id.
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The callback receives the answer and updates the form field.
7. What is the difference between a Business Rule and a Script Include?
A Business Rule runs automatically when its configured database operation or condition occurs. A Script Include contains reusable logic that other scripts can call.
For example, you can create a Script Include to calculate an employee's eligibility and call it from multiple Business Rules instead of duplicating the same code.
8. What are the parameters?
-
sysparm_name: The method to execute.
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sysparm_type: An optional parameter used by some implementations; it has no universal special meaning.
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sysparm_value: A custom parameter commonly used to pass a value.
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sysparm_caller_id: A custom parameter containing the selected caller's sys_id.
You retrieve custom parameters using:
var callerId = this.getParameter('sysparm_caller_id');
9. Synchronous vs. asynchronous
With asynchronous GlideAjax, ServiceNow sends the request and continues running other client-side code. The callback executes when the response arrives.
Avoid synchronous requests because they can block the browser while waiting for the server.
One important point: always validate input and enforce appropriate access controls on the server. Client-callable does not mean every user should be allowed to retrieve every piece of data.
If this helped, mark it helpful and accept the solution.
Regards,
Tejas
