JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/dot-luv/jquery-ui.css">
<div class="ui-selected">
    <div class="user-name">User 1</div>
    <div class="user-name">User 2</div>
    <div class="user-name">User 3</div>
    <div class="user-name">User 4</div>
</div>

JavaScript

var usersString = $(".ui-selected .user-name").map(function() {
                    return $(this).html(); //or this.innerHTML
                  }).get().join(',');
alert(usersString);