Reactive Backgrounds Animation — Reference
Interactive Dots
The Interactive Dots is a CSS animation component that a canvas-based dot grid background where dots scale and pulse in response to mouse movement and click ripples, creating an organic interactive feel. It ships as self-contained HTML and CSS with no external dependencies, making it drop-in ready for any modern web project regardless of framework or build system.
When to use the Interactive Dots
- Chat typing indicators, inline loading, and message delivery states
- Full-bleed hero sections, modal backdrops, and page wrappers
- Component libraries and design systems that need consistent motion patterns
- Progressive enhancement — works in all modern browsers, degrades gracefully
Performance characteristics
- GPU-accelerated — uses CSS transform and opacity so compositing happens off the main thread
- Zero JavaScript dependency in most configurations — no framework, no bundler required
- Approximately 60 fps on any device that supports CSS animations (Chrome 43+, Firefox 16+, Safari 9+)
- Self-contained in a single HTML file — no npm install, no build step, paste and ship
How it compares
Unlike equivalent JavaScript implementations, the Interactive Dots does not require any runtime library — there is nothing to install, bundle, or load asynchronously.
Compared to animated GIFs or video embeds, this CSS component is resolution-independent, theme-able via CSS custom properties, and weighs a fraction of the equivalent media file.
Source code
CSS
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { width: 100%; height: 100%; overflow: hidden; background: #F0EEE6; }
canvas { display: block; width: 100%; height: 100%; }HTML
<canvas id="c"></canvas>Full source
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<style>
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { width: 100%; height: 100%; overflow: hidden; background: #F0EEE6; }
canvas { display: block; width: 100%; height: 100%; }
</style>
</head>
<body>
<canvas id="c"></canvas>
<script>
var BG = '#F0EEE6';
var DC = '#666666';
var GS = 30;
var SPEED = 0.005;
var REMOVE_WAVE = true;
function hexRgb(h) {
var c = h.charAt(0) === '#' ? h.slice(1) : h;
return { r: parseInt(c.slice(0,2),16), g: parseInt(c.slice(2,4),16), b: parseInt(c.slice(4,6),16) };
}
var canvas = document.getElementById('c');
var time = 0;
var mouse = { x: 0, y: 0, down: false };
var ripples = [];
var dots = [];
function initDots() {
dots = [];
var W = canvas.clientWidth, H = canvas.clientHeight;
for (var x = GS/2; x < W; x += GS) {
for (var y = GS/2; y < H; y += GS) {
dots.push({ ox: x, oy: y, phase: Math.random()*Math.PI*2 });
}
}
}
function resize() {
var dpr = window.devicePixelRatio || 1;
canvas.width = innerWidth * dpr;
canvas.height = innerHeight * dpr;
canvas.style.width = innerWidth + 'px';
canvas.style.height = innerHeight + 'px';
canvas.getContext('2d').scale(dpr, dpr);
initDots();
}
function mouseFx(x, y) {
var d = Math.sqrt((x-mouse.x)*(x-mouse.x)+(y-mouse.y)*(y-mouse.y));
return Math.max(0, 1-d/150);
}
function rippleFx(x, y, now) {
var tot = 0;
for (var k=0; k<ripples.length; k++) {
var r = ripples[k];
var age = now - r.t;
if (age < 3000) {
var dx = x-r.x, dy = y-r.y;
var dist = Math.sqrt(dx*dx+dy*dy);
var rad = age/3000*300, w = 60;
if (Math.abs(dist-rad) < w) tot += (1-age/3000)*r.i*(1-Math.abs(dist-rad)/w);
}
}
return Math.min(tot, 2);
}
function draw() {
var ctx = canvas.getContext('2d');
time += SPEED;
var now = Date.now();
var W = canvas.clientWidth, H = canvas.clientHeight;
var dc = hexRgb(DC);
ctx.fillStyle = BG;
ctx.fillRect(0, 0, W, H);
for (var i=0; i<dots.length; i++) {
var dot = dots[i];
var mf = mouseFx(dot.ox, dot.oy);
var rf = rippleFx(dot.ox, dot.oy, now);
var inf = mf+rf;
var size = 2+inf*6+Math.sin(time+dot.phase)*0.5;
var opacity = Math.max(0.3, 0.6+inf*0.4+Math.abs(Math.sin(time*0.5+dot.phase))*0.1);
ctx.beginPath();
ctx.arc(dot.ox, dot.oy, size, 0, Math.PI*2);
ctx.fillStyle = 'rgba('+dc.r+','+dc.g+','+dc.b+','+opacity+')';
ctx.fill();
}
if (!REMOVE_WAVE) {
for (var k=0; k<ripples.length; k++) {
var r2 = ripples[k];
var age2 = now-r2.t;
if (age2 < 3000) {
var p = age2/3000;
ctx.beginPath();
ctx.strokeStyle = 'rgba(100,100,100,'+(1-p)*0.3*r2.i+')';
ctx.lineWidth = 2;
ctx.arc(r2.x, r2.y, p*300, 0, Math.PI*2);
ctx.stroke();
ctx.beginPath();
ctx.strokeStyle = 'rgba(120,120,120,'+(1-p)*0.2*r2.i+')';
ctx.lineWidth = 1;
ctx.arc(r2.x, r2.y, p*150, 0, Math.PI*2);
ctx.stroke();
}
}
}
requestAnimationFrame(draw);
}
resize();
window.addEventListener('resize', function() { resize(); });
canvas.addEventListener('mousemove', function(e) {
var rect = canvas.getBoundingClientRect();
mouse.x = e.clientX-rect.left; mouse.y = e.clientY-rect.top;
});
canvas.addEventListener('mousedown', function(e) {
mouse.down = true;
var rect = canvas.getBoundingClientRect();
ripples.push({ x: e.clientX-rect.left, y: e.clientY-rect.top, t: Date.now(), i: 2 });
var now = Date.now();
ripples = ripples.filter(function(r){ return now-r.t < 3000; });
});
canvas.addEventListener('mouseup', function(){ mouse.down = false; });
draw();
</script>
</body>
</html>Frequently asked questions
How do I add the Interactive Dots to my project?
Copy the full source code from the code block on this page. Paste the <style> block into your stylesheet (or a <style> tag in your HTML head) and the HTML markup into your template. No npm install or build step is required — the animation is self-contained. To customize colors, speed, or size, use Grepped's workspace at grepped.dev/animations/reactive-backgrounds/interactive-dots.
Is the Interactive Dots free to use?
Yes. All Grepped preset animations are free to use in personal and commercial projects. You may copy, modify, and redistribute the code without attribution. The only limitation is that you may not resell the presets themselves as part of a competing animation library.
Does the Interactive Dots work on mobile browsers?
Yes. The Interactive Dots uses standard CSS animations and transforms that are supported in all modern mobile browsers — Chrome for Android, Safari on iOS 9+, Samsung Internet, and Firefox for Android. Where JavaScript is used for interactivity (e.g. cursor effects), it falls back gracefully on touch devices.
Can I customize the Interactive Dots's colors, speed, or size?
Yes. Open the live customization workspace at grepped.dev/animations/reactive-backgrounds/interactive-dots to adjust the animation with real-time sliders, color pickers, and toggles — no code required. For deeper changes, the source code uses CSS custom properties (variables) so you can edit them directly in your stylesheet.
Want to customize this animation or generate a new one from a text prompt?
Open in Workspace — it's free