question Re: what is the difference between onload client script and onchange client script. in Community Central forum

what is the difference between onload client script and onchange client script.

ImmadisettyP — Tue, 18 Feb 2025 19:03:28 GMT

Re: what is the difference between onload client script and onchange client script.

Kieran Anson — Tue, 18 Feb 2025 23:25:16 GMT

If you're new to ServiceNow, I recommend reviewing the content on the developer website.

https://developer.servicenow.com/dev.do#!/learn/learning-plans/xanadu/new_to_servicenow/app_store_learnv2_scripting_xanadu_client_script_types

Re: what is the difference between onload client script and onchange client script.

AshishKM — Tue, 18 Feb 2025 23:37:11 GMT

Hi @ImmadisettyP,

Refer the belo , also check the developer portal link shared by @Kieran Anson .

In HTML, "onload" is an event that fires when an entire webpage has finished loading, including all its elements like images and scripts, while "onchange" is an event that occurs when the value of a specific HTML element (like a text input or dropdown menu) is changed by the user

onChange - Client Scripts execute script logic when a particular field's value changes.

onLoad - Client Scripts execute script logic when forms are loaded.

-Thanks,

AshishKM

Re: what is the difference between onload client script and onchange client script.

Debasis Pati — Wed, 19 Feb 2025 01:56:42 GMT

Hello @ImmadisettyP

onLoad means the Client Script runs when the form or page is loaded
onChange means the Client Script runs when something specific gets changed AND also when the form or page loads
Additional parameter for onChange client script is : isLoading - identifies whether the form is loading and also indicates that no fields have changed value. This parameter can only be true when the form is loading and no values have changed.

To know more about client scripts please go through - https://www.servicenow.com/docs/bundle/yokohama-api-reference/page/script/client-scripts/concept/client-scripts.html

If my answer helps you please mark it as helpful/correct.

Regards,
Debasis

Re: what is the difference between onload client script and onchange client script.

dgarad — Wed, 19 Feb 2025 02:24:39 GMT

Hi @ImmadisettyP

onLoad means the Client Script runs when the form or page is loaded
onChange means the Client Script runs when something specific gets changed AND also when the form or page loads

Additional parameter for onChange client script is : isLoading - identifies whether the form is loading and also indicates that no fields have changed value. This parameter can only be true when the form is loading and no values have changed.

Re: what is the difference between onload client script and onchange client script.

Raahul2 — Wed, 19 Feb 2025 03:05:35 GMT

Both onLoad and onChange client scripts are used to run JavaScript code on the client-side (i.e., in the user's browser,client side), but they have different purposes and triggering conditions.
onLoad Client Script:
- Trigger condition: Runs when a record form is loaded (opened or refreshed).
- Purpose: It’s typically used to manipulate the form or perform actions when the form first appears to the user. For example, setting default values or hiding/showing fields.
- Example: Hiding a field when the form loads.
onChange Client Script:
- Trigger condition: Runs when the value of a specific field on the form changes.
- Purpose: It’s used to perform actions based on changes to a particular field, such as validating input or triggering other changes on the form when the field value is modified.
- Example: Displaying a message or updating other fields when a user selects a value in a dropdown field.

Please mark this response as correct and helpful if it helps you can mark more that one reply as accepted solution