get user_name from List Collector (sys_user) and put user+user_name into hidden variable

[Community Alums]

I have a catalog item with a list collector that gathers multiple users. When that variable comes through on the ritm/task, it's just a list of names. What is desired is for their user_name to also appear. However, I don't want a separate field on the form that they see when they're filling this out; I only want it to be passed to the ritm/task after the form is submitted. I thought I'd make a multiline textbox variable that could fill in the users and their usernames in this format: 

    Bob User [bob123]

    Sally User [sally456]

by using a client script and script include. Neither is working and when I submit the form, I get 'Unhandled exception in GlideAjax'. Can you please look at what I have and help? 

Here is the client script (ui type=all; applies to cat item, ritm, task): 

function onSubmit() {
   //array of sys_ids from list collector variable 
    var usersToAdd = g_form.getValue('persons_requiring_access').toString().split(',');

    var ga = new GlideAjax('GetListCollectorVariables'); //call the script include
    ga.addParam('sysparm_name', 'UsersListCollector'); //name of function in script include
    ga.addParam('sysparm_users', usersToAdd); //pass array of users to SI
    ga.getXML(GetVariables);

    function GetVariables(response) {
        var answer = response.responseXML.documentElement.getAttribute('answer');
        g_form.setValue('persons_requiring_access_text', answer);
    }
   
}

Here is the script include (client callable = true; global scope) 

var GetListCollectorValues = Class.create();
GetListCollectorValues.prototype = Object.extendsObject(global.AbstractAjaxProcessor, {
    UsersListCollector: function() {
		var userInfo = '';
		var usersFromListCollector = this.getParameter('sysparm_users');
		var grUser = new GlideRecord('sys_user');
		grUser.addQuery('sys_id','IN',usersFromListCollector);
		grUser.query();
		while(grUser.next()) { 
			userInfo += grUser.name + ' [' + grUser.user_name + ']';
		}
		return info.toString();
    },
    type: 'GetListCollectorValues'
});

[Harsh Vardhan]

try now, also check what are you getting in alert . 

function onSubmit() {
   //array of sys_ids from list collector variable 
    var usersToAdd = g_form.getValue('persons_requiring_access').toString();

    var ga = new GlideAjax('GetListCollectorVariables'); //call the script include
    ga.addParam('sysparm_name', 'UsersListCollector'); //name of function in script include
    ga.addParam('sysparm_users', usersToAdd); //pass array of users to SI
    ga.getXML(GetVariables);

    function GetVariables(response) {
        var answer = response.responseXML.documentElement.getAttribute('answer');
var op = JSON.parse(answer);
alert(op.name + '  ' + op.u_name);
        //g_form.setValue('persons_requiring_access_text', answer);
    }
   
}

var GetListCollectorValues = Class.create();
GetListCollectorValues.prototype = Object.extendsObject(global.AbstractAjaxProcessor, {
    UsersListCollector: function() {
		var obj = {};
var json = new JSON();
		var usersFromListCollector = this.getParameter('sysparm_users').toString().split(',');
for(var i = 0 ; i < usersFromListCollector.length ; i ++){
		var grUser = new GlideRecord('sys_user');
		grUser.addQuery('sys_id','IN',usersFromListCollector[i]);
		grUser.query();
		while(grUser.next()) { 

obj.name = grUser.name+'';
obj.u_name = grUser.user_name +'';
			json.encode(obj);
		
		}
}
		return json;
    },
    type: 'GetListCollectorValues'
});

[Community Alums]

ok I updated my code to yours but didn't get an alert; instead got a JS error

[Harsh Vardhan]

please check my last response, i have mentioned working script, which i have tested at my end and working. 

[Harsh Vardhan]

Also would it possible to use this on onChange instead of onSubmit ?