The <canvas> element is a new element apart of HTML5. It allows you to draw shapes, paths, images, and other drawings on a blank element called the canvas.
Canvas元素是HTML5独立的新元素，它允许你在调用了画布的空元素上，画形状、路径、图像和其它绘制功能。

Before you can draw on the canvas, you need to create one.
在画布上绘制之前，你需要创建一个画布。

<canvas width='300' height='150'></canvas>

Of course, the canvas can be any width/height you want. You may also wish to give the canvas an ID (for future reference).
当然，画布可以是任意你想要的宽高，你也可以给画布设置一个ID（用于未来引用它）。
As a side note, you cannot accurately set a canvas's width and height via CSS; you can only do so through the canvas element's width and height attributes.
作为侧面说明，你无法通过CSS来精确的设置画布的宽高，你只能通过画布元素的宽高属性来这么做（设置宽高）。

You also need to add jCanvas to your page somehow (usually a <script> element will do).
你也需要将jCanvas用某种方法加到你的页面上（通常用script元素就可以了）。

<script src='jcanvas.min.js'></script>

HTML5 provides a native JavaScript API for drawing on the canvas. However, we will be using jCanvas instead.
HTML5提供了一个本地JS接口，用来在画布上绘图。但我们要使用jCanvas代替。
Using jCanvas requires basic knowledge of using jQuery.
使用jCanvas需要掌握使用jQuery的基本知识。