北京网站推广【北京官网推广哪个效果好】北京百度竞价推广托管、北京百度优化推广外包、北京全网霸屏推广多少钱、北京网络推广一年大概多少费 ​

书写hmtl代码。<canvas id="c" width="1680" height="895"></canvas>

书写css代码。<style>canvas { position: absolute; top: 0; left: 0; background-color: black; }</style>

书写并添加js代码。<script>var w = c.width = window.innerWidth,    h = c.height = window.innerHeight,    ctx = c.getContext('2d'),        count = (w*h/3000)|0,    speed = 4,    range = 80,    lineAlpha = .05,        particles = [],    huePart = 360/count;for(var i = 0; i < count; ++i)  particles.push(new Particle((huePart*i)|0));function Particle(hue){  this.x = Math.random()*w;  this.y = Math.random()*h;  this.vx = (Math.random()-.5)*speed;  this.vy = (Math.random()-.5)*speed;    this.hue = hue;}Particle.prototype.update = function(){  this.x += this.vx;  this.y += this.vy;    if(this.x < 0 || this.x > w) this.vx *= -1;  if(this.y < 0 || this.y > h) this.vy *= -1;}function checkDist(a, b, dist){  var x = a.x - b.x,      y = a.y - b.y;    return x*x + y*y <= dist*dist;}function anim(){  window.requestAnimationFrame(anim);    ctx.fillStyle = 'rgba(0, 0, 0, .05)';  ctx.fillRect(0, 0, w, h);    for(var i = 0; i < particles.length; ++i){    var p1 = particles[i];    p1.update();        for(var j = i+1; j < particles.length; ++j){      var p2 = particles[j];      if(checkDist(p1, p2, range)){        ctx.strokeStyle = 'hsla(hue, 80%, 50%, alp)'          .replace('hue', ((p1.hue  + p2.hue + 3)/2) % 360)          .replace('alp', lineAlpha);        ctx.beginPath();        ctx.moveTo(p1.x, p1.y);        ctx.lineTo(p2.x, p2.y);        ctx.stroke();      }    }  }}anim();</script>

代码整体结构。

查看效果。