fillRect(100,100,100,100) The first two 100s refer to the coordinates, and the last two 100s refer to the width and height.
Today I was learning HTML5 canvas and found that the coordinates and size of fillRect were always wrong. After studying for a long time, I found that the width and height of canvas must be inline in the canvas tag. I was depressed for a long time.
Wrong way 1:
