Why this lines? Can anyone one explain each code and its work?

Question

var c=document.getElementById("canvas1");
var ctx=c.getContext("2d");
ctx.fillRect(20,20,100,100);

Answer 1

var c = document.getElementById("canvas1");
this gets your html canvas element(by its id which is canvas1), and stores it in the var c.

var ctx = c.getContext("2d");
this creates your drawing context of the canvas

ctx.fillRect(20,20,100,100);
this draws a rectangle in your canvas context, at the position (x)20, (y)20, size of (width)100,(height)100

Answer 2

wow.! thank you buddy

Answer 3

you're welcome :)