Book Image

Web Developer's Reference Guide

By : Joshua Johanan, Talha Khan, Ricardo Zea
Book Image

Web Developer's Reference Guide

By: Joshua Johanan, Talha Khan, Ricardo Zea

Overview of this book

This comprehensive reference guide takes you through each topic in web development and highlights the most popular and important elements of each area. Starting with HTML, you will learn key elements and attributes and how they relate to each other. Next, you will explore CSS pseudo-classes and pseudo-elements, followed by CSS properties and functions. This will introduce you to many powerful and new selectors. You will then move on to JavaScript. This section will not just introduce functions, but will provide you with an entire reference for the language and paradigms. You will discover more about three of the most popular frameworks today—Bootstrap, which builds on CSS, jQuery which builds on JavaScript, and AngularJS, which also builds on JavaScript. Finally, you will take a walk-through Node.js, which is a server-side framework that allows you to write programs in JavaScript.
Table of Contents (22 chapters)
Web Developer's Reference Guide
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
9
JavaScript Expressions, Operators, Statements, and Arrays
Index

Drawing elements


In previous versions of HTML, if you wanted a graphic or image, you had to create it in another application and use the img element to pull it into your document. HTML5 has brought some new elements and features to replace the old elements that allow you to draw your own images in the browser.

canvas

The syntax of the canvas element is as follows:

<canvas height width></canvas>

Attributes

The attributes that are used in the canvas element are as follows:

  • height: This is an attribute to set the height

  • width: This is an attribute to set the width

Description

The canvas element is used for drawing. You can use JavaScript to draw lines, shapes, and images; pull frames from videos; and use WebGL, to name just a few features. The HTML element is just the canvas (aptly named!) that you use to make a drawing. All of the interaction happens in JavaScript.

Here is an example of a small canvas element:

<canvas height="400" width="400">
    Your browser does not support the canvas element.
</canvas>

svg

The svg element is the Scalable Vector Graphics (SVG) element:

<svg height viewbox width ></svg>

Attributes

The attributes that are used in the svg element are as follows:

  • height: This is the attribute that sets the height.

  • viewbox: This sets the bounds for the element. It takes four numbers that map to min-x, min-y, width, and height.

  • width: This is the attribute that sets the width.

Description

SVG is not a true HTML element. It is its own specification with many elements and attributes. There are books written entirely about SVG. This element is here because you can now create inline SVG in an HTML document. This gives you a lot of flexibility with two-dimensional drawings that images do not give you.

Here is an example that demonstrates the difference between height, width, and viewport. The viewport takes up the bounds of the element, and height and width give the element its size:

<svg xmlns="http://www.w3.org/2000/svg" preserveAspectRatio=""
    width="200" height="100" viewBox="0 0 400 200">
    <rect x="0" y="0" width="400" height="200" fill="yellow" stroke="black" stroke-width="3" />
</svg>