the canvas element is created with the id "myCanvas" and a width of 200 pixels and a height of 100 pixels. The JavaScript code gets the canvas element using the getElementById() method and gets the 2D context for drawing using the getContext() method.

The ctx.fillStyle property sets the color to fill the rectangle, and the ctx.fillRect() method is used to draw the rectangle on the canvas.

You can use a variety of other methods and properties to draw shapes, text, images, and animations on the canvas, depending on your needs. With the canvas element, you can create dynamic and interactive web pages with rich graphics and visual effects.