What is the usage of a canvas element in HTML 5?

Question

How and When is it used?

Answer 1

<canvas> is an element in HTML5 that we can use to draw graphics using scripting (that is most probably JavaScript). 

This element behaves like a container for graphics and the rest will be done by scripting. We can draw images, graphs and a bit of animations etcetera using a element.

<canvas id="canvas1" width="300" height="100">
</canvas>

Answer 2

The HTML element is used to draw graphics, on the fly, via scripting (usually JavaScript). The element is only a container for graphics. You must use a script to actually draw the graphics.