Script not running in native UI

[SHALIKAS]

I have written an onChange client script on server_name variable which is a list collector variable. This script is working in portal, but not in native UI

In native UI even the alert is not coming

function onChange(control, oldValue, newValue, isLoading) {

    if (isLoading || !newValue) {

        return;

    }

    // Get first selected server from list collector

    var firstServer = newValue.split(',')[0];

alert("firest"+firstServer);

    var ga = new GlideAjax('Coned_fetch_server_details');

    ga.addParam('sysparm_name', 'getServerDetails');

    ga.addParam('sysparm_sys_id', firstServer);

    ga.getXMLAnswer(function(answer) {

alert("Answer = [" + answer + "]");

        if (answer == 'Ansible') {

            g_form.setValue('task_for_automation', 'Yes');

        } else {

            g_form.setValue('task_for_automation', 'No');

        }

    });

}

The script include is

var Coned_fetch_server_details = Class.create();

Coned_fetch_server_details.prototype = Object.extendsObject(AbstractAjaxProcessor, {

    getServerDetails: function() {

        var serverId = this.getParameter('sysparm_sys_id');

        gs.info('Server Id = ' + serverId);

        var gr = new GlideRecord('cmdb_ci_server');

        if (gr.get(serverId)) {

            gs.info('Build Source = ' + gr.u_build_source);

            return gr.u_build_source.toString();

        }

        return '';

    },

    type: 'Coned_fetch_server_details'

});

[SHALIKAS]

It is not working, tried to add alert statement as well , the alert is also not coming