The HTML 5 canvas is a two-dimensional rectangular grid with the top left corner being the point with coordinates (0,0). If we label by x and y the horizontal and the vertical coordinates, the as we go from left to right the horizontal coordinate x increases from 0 to the width of the canvas. As we move from top to bottom the vertical coordinate y increases from 0 to the height of the canvas. In the example shown below, the canvas has a width of 400 pixels and a height of 400 pixels. Some of the points on the grid have their coordinates (x,y) in pixels.
The canvas element is an HTML 5 element used within the body of an HTML 5 file in order to create a canvas as follows:
<canvas id="myFirstCanvas" width="400" height="400" style="border:4px solid #0000ff;">
This browser does not support the HTML5 canvas tag. </canvas>
Free HTML5 Canvas Tutorials