Erasing part of what you have created might seem contradictory at first. But when you, for example, try to create a semicircle in SVG, you will find out the use of the following properties quickly:

JavaScript supports a compact set of statements, specifically control flow statements, that you can use to incorporate a great deal of interactivity in your application. This chapter provides an overview of these statements.

A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). In other words, a closure gives you access to an outer function's scope from an inner function. In JavaScript, closures are created every time a function is created, at function creation time.

Now we're ready to start distorting our beautiful images. But first, let's formally introduce the <g> element. With this helper, you can assign properties to a complete set of elements. Actually, that's its only purpose.

The <switch> SVG element evaluates any requiredFeatures, requiredExtensions and systemLanguage attributes on its direct child elements in order, and then renders the first child where these attributes evaluate to true.

The function declaration creates a binding of a new function to a given name.

The decoding attribute, valid on <image> elements, provides a hint to the browser as to whether it should perform image decoding along with rendering other content in a single presentation step that looks more "correct" (sync), or render and present the other content first and then decode the image and present it later (async). In practice, async means that the next paint does not wait for the image to decode.

The dy attribute indicates a shift along the y-axis on the position of an element or its content.

The JavaScript exception "invalid Array.prototype.sort argument" occurs when the argument of Array.prototype.sort() isn't either undefined or a function which compares its operands.

Whereas HTML defines a webpage's structure and content and CSS sets the formatting and appearance, JavaScript adds interactivity to a webpage and creates rich web applications.