HTML JavaScript Canvas

I am building a multi user shared drawing game where everyone can paint on the same screen. I started with the HTML5 canvas because it is simple and fast, and it avoids DOM work. I debated using a grid of divs with CSS for fun animations, but canvas feels like the best first step and we can switch later. I set the real canvas resolution with the width and height attributes, not just CSS, then fixed a bug where the drawing looked scaled by mapping the mouse position from page size into canvas size. Next I added event listeners so a click gives me offset x and y, then I upgraded it to click and drag by drawing lines with beginPath, moveTo, lineTo, and stroke. After that I planned a basic color picker so people can draw in different colors. The goal is to finish single player drawing first, then add realtime multi user so chat can draw together.