Most modern web applications are built upon a foundation of HTML pages that describe the content that users read and interact with, style sheets to make that content visually pleasing, and JavaScript code to provide a level of interactivity between user and page, and page and server. The web browser uses the HTML markup and the style sheets to render this content, and runs the JavaScript code to implement the behavior of the application. This module reviews the basics of HTML and CSS, and introduces the tools that this course uses to create HTML pages and style sheets.

The technologies forming the basis of all web applications HTML, CSS, and JavaScript have been available for many years, but the purpose and sophistication of web applications have changed significantly. HTML5 is the first major revision of HTML in 10 years, and it provides a highly suitable means of presenting content for traditional web applications, applications running on handheld mobile devices, and also on the Windows 10 platform. This module introduces HTML5, describes its new features, demonstrates how to present content by using the new features in HTML5, and how to style this content by using CSS.

HTML and CSS provide the structural, semantic, and presentation information for a web page. However, these technologies do not describe how the user interacts with a page by using a browser. To implement this functionality, all modern browsers include a JavaScript engine to support the use of scripts in a page. They also implement Document Object Model (DOM), a W3C standard that defines how a browser should reflect a page in memory to enable scripting engines to access and alter the contents of that page. This module introduces JavaScript programming and DOM.

Web applications frequently need to gather user input in order to perform their tasks. A web page needs to be clear and concise about the input expected from a user in order to minimize frustrating misunderstandings about the information that the user should provide. Additionally, all input must be validated to ensure that it conforms to the requirements of the application. In this module, you will learn how to define input forms by using the new input types available in HTML5. You will also see how to validate data by using HTML5 attributes. Finally, you will learn how to perform extended input validation by using JavaScript code, and how to provide feedback to users when their input is not valid or does not match the applications expectations.

Many web applications require the use of data held by a remote site. In some cases, you can access this data simply by downloading it from a specified URL, but in other cases the data is encapsulated by the remote site and made accessible through a web service. In this module, you will learn how to access a web service by using JavaScript code and to incorporate remote data into your web applications. You will look at two technologies for achieving this: the XMLHttpRequest object, which acts as a programmatic wrapper around HTTP requests to remote web sites, and Fetch API, which simplifies many of the tasks involved in sending requests and receiving data. Because the Fetch API and the XMLHttpRequest object are asynchronous api You will first learn about how to handle asynchronous tasks with the Promise object, arrow functions and the new async/await syntax that lets you handle asynchronous request as if they were synchronous.

Styling the content displayed by a web page is an important aspect of making an application attractive and easy to use. CSS is the principal mechanism that web applications use to implement styling, and the features added to CSS3 support many of the new capabilities found in modern browsers. Where CSS1 and CSS2.1 were single documents, the World Wide Web Consortium has chosen to write CSS3 as a set of modules, each focusing on a single aspect of presentation such as color, text, box model, and animations. This allows the specifications to develop incrementally, along with their implementations. Each specification defines properties and values that already exist in CSS1 and CSS2, and also new properties and values. In this module, you will examine the properties and values defined in several of these modules, the new selectors defined in CSS3, and the use of pseudo-classes and pseudo-elements to refine those selections.

Code reuse and ease of maintenance are key objectives of writing well-structured applications. If you can meet these objectives, you will reduce the costs associated with writing and maintaining your code. This module describes how to write well-structured JavaScript code by using language features such as namespaces, objects, encapsulation, and inheritance. These concepts might seem familiar if you have experience in a language such as Java or C#, but the JavaScript approach is quite different and there are many subtleties that you must understand if you want to write maintainable code.

Interactivity is a key aspect of modern web applications, enabling you to build compelling web sites that can quickly respond to the actions of the user, and also adapt themselves to the user’s location. This module describes how to create interactive HTML5 web applications that can access the local file system, enable the user to drag-and-drop data onto elements in a web page, play multimedia files, and obtain geolocation information.

Web applications have a dependency on being able to connect to a network to fetch web pages and data. However, in some environments a network connection may be intermittent. In these situations, it might be useful to enable the application to continue functioning by using data cached on the user’s device. HTML5 provides a choice of new client-side storage options, including session storage and local storage, and a resource caching mechanism called the Application Cache. In this module, you will learn how to use these technologies to create robust web applications that can continue running even when a network connection is unavailable.

One of the most enduring features of the web is its temporary nature. For the first time, the monopoly of the keyboard and mouse is coming under challenge, and that means questioning how user interfaces are designed. You may develop a web application on a computer with a large, high-resolution monitor, a mouse, and a keyboard, but other users might view and interact with your application on a smartphone or a tablet without a mouse, or have a monitor with a different resolution. Users may also want to print pages of your application. In this module, you will learn how to build a website that adapts the layout and functionality of its pages to the capabilities and form factor of the device on which it is being viewed. You will see how to detect the type of device being used to view a page, and learn strategies for laying out content that effectively targets particular devices.

High-resolution, interactive graphics are a key part of most modern applications. Graphics can help to enhance the user’s experience by providing a visual aspect to the content, making a website more attractive and easier to use. Interactivity enables the graphical elements in a website to adapt and respond to user input or changes to the environment, and is another important element in retaining the attention of the user and their interest in the content. This module describes how to create advanced graphics in HTML5 by using Scalable Vector Graphics (SVG) and the Microsoft Canvas API. You will learn how to use SVG-related elements such as, and to display graphical content on a web page. You will also learn how to enable the user to interact with SVG elements through the use of events such as keyboard events and mouse events. The Canvas API is somewhat different than SVG. The Canvas API provides a element and a set of JavaScript functions that you can invoke to draw graphics onto the canvas surface. You will learn how to use the Canvas API, and also find out when it is more appropriate to use Canvas or SVG.

Animations are a key element in maintaining the interest of a user in a website. Implemented carefully, animations improve the usability of a web page and provide useful visual feedback on user actions. This module describes how to enhance web pages by using CSS animations. You will learn how to apply transitions to property values. Transitions enable you to specify the timing of property changes. For example, you can specify that an element should change its width and height over a five-second period when the mouse pointer hovers over it. Next, you will learn how to apply 2D and 3D transformations to elements. Transformations enable you to scale, translate, rotate, and skew elements. You can also apply transitions to transformations, so that the transformation is applied gradually over a specified animation period. At the end of this module, you will learn how to apply keyframe animations to elements. Keyframe animations enable you to define a set of property values at specific moments during an animation. For example, you can specify the color and position of an element at 0 percent, 33 percent, 66 percent, and 100 percent of the animation period.

Web pages request data on demand from a web server by submitting HTTP requests. This model is ideal for building interactive applications, where the functionality is driven by the actions of a user. However, in an application that needs to display constantly changing information, this mechanism is less suitable. For example, a financial stocks page is worthless if it shows prices that are even a few minutes old, and you cannot expect a user to constantly refresh the page displayed in the browser. This is where web sockets are useful. The Web Sockets API provides a mechanism for implementing real-time, two-way communication between web server and browser.This module introduces web sockets, describes how they work, and explains how to create a web socket connection that can be used to transmit data in real time between a web page and a web server.

JavaScript code is a powerful tool for implementing functionality in a web page, but you need to remember that this code runs either when a web page loads or in response to user actions while the web page is being displayed. The code is run by the browser, and if the code performs operations that take a significant time to complete, the browser can become unresponsive and degrade the user’s experience. HTML5 introduces web workers, which enable you to offload processing to separate background threads and thus enable the browser to remain responsive. This module describes how web workers operate and how you can use them in your web applications.

Using models allows you to build large, complex applications. The progress of the language in the version of ECMAScript6 allows the build app with to simplify the application construction process. However, the use of ECMAScript6 modules and other features is not yet supported in all browsers. Tools such as Node.js, Webpack, and Babel enable the use of new language features along with support for different browsers in order to avoid harming the user experience. In this module we will introduce the theory behind these tools, when we need to used them, and the different options for use. At the end of the module we will see how to use these tools to write ECMAScript6 code supported in all browsers.