Getting started with onsen-ui – Introduction

Onsen UI is an open-source framework that helps you build hybrid apps with native like performance. It can be used along with several well known JavaScript frameworks such as AngularJS (1 & 2), ReactJS and jQuery.

Loading OnsenUI in a project is as easy as writing some standard tags of HTML in your index.html file:

<!doctype html>
    <html lang="en">
        <meta charset="utf-8">
        <!-- load Onsen structure CSS file -->
        <link rel="stylesheet" href="lib/onsen/css/onsenui.css"/>
        <!-- load Onsen theme CSS file -->
        <link rel="stylesheet" href="lib/onsen/css/onsen-css-components.css"/>
        <!-- load Onsen main Javascript file -->
        <script src="lib/onsen/js/onsenui.js"></script>
          ons.ready(function() {
            // Init code here
            Hello World!

ons.ready function is the main function that can safely tell us when Onsen UI initialization is done. Then you can use any of OnsenUI components.

if you want to reproduce, please indicate the source:
Getting started with onsen-ui – Introduction - CodeDay