How do I get the width and height of a HTML5 canvas?

Question

How can i get the width and height of the canvas element in JavaScript?

Also, what is the \"context\" of the canvas I keep reading about?

Answer 1

The context object allows you to manipulate the canvas; you can draw rectangles for example and a lot more.

If you want to get the width and height, you can just use the standard HTML attributes width and height:

var canvas = document.getElementById( 'yourCanvasID' );
var ctx = canvas.getContext( '2d' );

alert( canvas.width );
alert( canvas.height );