How to set a value on a field of the form or record in ServiceNow?

In this tutorial, you will learn how can you set a value on a field of a form on different conditions and scenarios.

Setting the field value on load of the form

Scenario: When incident form is loaded then the value of Caller field should populated with logged in user.

Solution : This type of requirement can be achieved with Client Script as it needs to be set when form is loaded in the browser.

Script Type : Client Script

Name : Populate Caller on the Incident

Table : Incident

UI Type : All

Type : OnLoad

Active : True

Global: True

Script : 

function onLoad() {
    //Type appropriate comment here, and begin script below

    if (g_form.isNewRecord()) {

        var currentUser = g_user.userID;

        g_form.setValue('caller_id', currentUser);
    }
}

Setting the field value on change of a field

Scenario: When incident form is loaded then the Assignment Group should be populated with Network group.

Solution : This type of requirement can be achieved with Client Script as it needs to be set when value oof Category field changes to Hardware.

Script Type : Client Script

Name : Populate Caller on the Incident

Table : Incident

UI Type : All

Type : OnChange

Field: Category

Active : True

Global: True

Script : 

function onChange(control, oldValue, newValue, isLoading, isTemplate) {
    if (isLoading || newValue === '') {
        return;
    }

    //Type appropriate comment here, and begin script below
    if (newValue == 'hardware') {
        //Setting SYSID OF Network Group
        g_form.setValue('assignment_group', '287ebd7da9fe198100f92cc8d1d2154e'
        ,'Network'); 
    }

}