All drawing on the HTML canvas must be done with JavaScript:
First of all, you must find find the <canvas> element.
This is done by using the HTML DOM method getElementById():
Secondly, you need a drawing object for the canvas.
The canvas context is a built-in HTML object, with properties and methods for drawing.
You create a canvas drawing object by calling the canvas method getContext("2d"):
Finally, you can draw on the canvas.
Set the fill style of the drawing object to the color red:
The fillStyle property can be a CSS color, a gradient, or a pattern. The default is #000000 (black).
The fillRect(x,y,width,height) method draws a rectangle, filled with the fill style, on the canvas.
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