You'll need your onSubmit script to call a GlideAjax with the variable value. The Script Include will query the referenced table and return a list of the display values. So something like this if we're talking about a list collector on the sys_user table. If you're using Service Portal, you'll need to do something else as the submit will complete before the response is received from the server, so the confirmation will appear after the request has been created.
function onChange(control, oldValue, newValue, isLoading) {
if (isLoading || newValue == '') {
return;
}
var ga = new GlideAjax('UserUtils'); //name of Script Include
ga.addParam('sysparm_name', 'getUsers'); //name of function
ga.addParam('sysparm_user', g_form.getValue('v_users'); //list collector variable name
ga.getXMLAnswer(function(answer){
confirm('Do you want to continue for ' + answer + '?');
});
}
Script Include with Client callable box checked
var UserUtils = Class.create();
UserUtils.prototype = Object.extendsObject(AbstractAjaxProcessor, {
getUsers: function() {
var answerArr = [];
var users = this.getParameter('sysparm_user');
var gr = new GlideRecord('sys_user');
gr.addQuery('sys_id', 'IN', users);
gr.query();
while (gr.next()) {
answerArr.push(gr.name);
}
return answerArr.join(', ');
},
type: 'UserUtils'
});
