Hi, This can be done through a onChange Client Script and a Script Include. I am assuming the Caller field is already populated with logged in user or some other user as you mentioned it is a read only field.
For Testing purpose I have 4 variables on catalog form "Caller" and "Requester" and I am populating "Email" and "Department".
So make sure you edit the below script as per your variable/field names
Client Script:
function onChange(control, oldValue, newValue, isLoading) {
if (isLoading) {
var getUserDetailsOnLoad = new GlideAjax('getUserDetails');
getUserDetailsOnLoad.addParam('sysparam_name', 'getUserDetailsMethod');
getUserDetailsOnLoad.addParam('sysparm_user', g_form.getValue('caller_id'));
getUserDetailsOnLoad.getXML(processUserDetails);
}
//Type appropriate comment here, and begin script below
var user;
if(newValue == ''){
user = g_form.getValue('caller_id'); //Caller ID
}else{
user = newValue; //Requester ID
}
var getUserDetails = new GlideAjax('getUserDetails');
getUserDetails.addParam('sysparm_name', 'getUserDetailsMethod');
getUserDetails.addParam('sysparm_user', user);
getUserDetails.getXML(processUserDetails);
}
function processUserDetails(response){
var answer = response.responseXML.documentElement.getAttribute('answer');
if(answer){
var receivedObj = JSON.parse(answer);
g_form.setValue('user_email', receivedObj.email);
g_form.setValue('user_dept', receivedObj.dept);
}
}
Client Callable Script Include:
var getUserDetails = Class.create();
getUserDetails.prototype = Object.extendsObject(AbstractAjaxProcessor, {
getUserDetailsMethod : function(){
var userObj= this.getParameter('sysparm_user');
var arr = {};
var user = new GlideRecord('sys_user');
user.get(userObj);
arr.email = user.email.toString();
arr.dept = user.department.getDisplayValue();
return JSON.stringify(arr);
},
type: 'getUserDetails'
});
On Load of form: Caller fields displayed:
On Selection of Requester: requester fields displayed
If Requester is made blank; Caller fields displayed again-
