JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span id=mybox1></span> Option 1<br>
    <span id=mybox2></span> Option 2<br>
    <span id=mybox3></span> Option 3<br>
    <span id=mybox4></span> Option 4 (has 3 states)<br>
    <hr>
    <p id=output></p>
    <hr>
</div>

JavaScript

Object.prototype.create = function(args){
    var retobj = Object.create(this);

    retobj.constructor(args || null);

    return retobj;
}

Object.prototype.extend = function(newobj){
    var oldobj = Object.create(this);
    
    for(prop in newobj)
        oldobj[prop] = newobj[prop];

    return Object.seal(oldobj);
}

var Checkbox = Object.seal({
    /* modified slightly to be more generic */
    width: 0,
    height: 0,
    state: 0,
    document: null,
    parent: null,
    canvas: null,
    ctx: null,

    /*
     * args:
     * name      default             desc.
     *
     * width     15                  width
     * height    15                  height
     * document  window.document     explicit document reference
     * target    this.document.body  target element to insert checkbox into
     */
    constructor: function(args){
        if(args === null)
            args = {};

        this.width = args.width || 15;
        this.height = args.height || 15;
        this.document = args.document || window.document;
        this.parent = args.target || this.document.body;
        this.canvas = this.document.createElement("canvas");
        this.ctx = this.canvas.getContext('2d');

        this.canvas.width = this.width;
        this.canvas.height = this.height;
        this.canvas.addEventListener("click", this.ev_click(this), false);
        this.parent.appendChild(this.canvas);
        this.draw();
    },

    ev_click: function(self){
        return function(unused){
            self.state = !self.state;
            self.draw();
        }
    },

    draw_rect: function(color, offsetx, offsety){
        this.ctx.fillStyle = color;
        this.ctx.fillRect(offsetx, offsety,
                this.width - offsetx * 2, this.height - offsety * 2);
    },

    draw: function(){
        this.draw_rect("#CCCCCC", 0, 0);
        this.draw_rect("#FFFFFF", 1, 1);
        this.draw_state();
    },

    draw_state: function(){
        if(this.is_checked())
    ...