jquery+css实现流星雨特效

案例效果：

代码如下：

js:

var stars = document.getElementById('stars')

  // js随机生成流星
  for (var j=0;j<30;j++) {
    var newStar = document.createElement("div")
    newStar.className = "star"
    newStar.style.top = randomDistance(500, -100) + 'px'
    newStar.style.left = randomDistance(1300, 300) + 'px'
    stars.appendChild(newStar)
  }
  
  // 封装随机数方法
  function randomDistance (max, min) {
    var distance = Math.floor(Math.random() * (max - min + 1) + min)
    return distance
  }
   var star = document.getElementsByClassName('star')

  // 给流星添加动画延时
  for (var i = 0, len = star.length; i < len; i++)
  {
　　  star[i].style.animationDelay = i % 6 == 0 ? '0s' : i * 0.8 + 's'
  }

css:

	 html, body {
      width: 100%;
      height: 100%;
      margin: 0;
      overflow: hidden;
      background: linear-gradient(rgba(0, 108, 172, 1), rgba(0, 122, 195, .7));
    }
    
    #stars {
      margin: 0 auto;
      max-width: 1600px;
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      z-index: 2;
    }
      .star {
      display: block;
　　　 width: 1px;
      background: transparent;
      position: relative;
      opacity: 0;
      /*过渡动画*/ 
      animation: star-fall 3s linear infinite;
      -webkit-animation: star-fall 3s linear infinite;
      -moz-animation: star-fall 3s linear infinite;
    }
    
    .star:after {
      content: '';
      display: block;
      border: 0px solid #fff;
      border-width: 0px 90px 2px 90px;
      border-color: transparent transparent transparent rgba(255, 255, 255, .5);
      box-shadow: 0 0 1px 0 rgba(255, 255, 255, .1);
      /*变形*/       
      transform: rotate(-45deg) translate3d(1px, 3px, 0);
      -webkit-transform: rotate(-45deg) translate3d(1px, 3px, 0);
      -moz-transform: rotate(-45deg) translate3d(1px, 3px, 0);
      transform-origin: 0% 100%;
      -webkit-transform-origin: 0% 100%;
      -moz-transform-origin: 0% 100%;
    }
      @keyframes star-fall {
      0% {
        opacity: 0;
        transform: scale(0.5) translate3d(0, 0, 0);
        -webkit-transform: scale(0.5) translate3d(0, 0, 0);
        -moz-transform: scale(0.5) translate3d(0, 0, 0);
      }
      50% {
        opacity: 1;
        transform: translate3d(-200px, 200px, 0);
        -webkit-transform: translate3d(-200px, 200px, 0);
        -moz-transform: translate3d(-200px, 200px, 0);
      }
      100% {
        opacity: 0;
        transform: scale(1.2) translate3d(-300px, 300px, 0);
        -webkit-transform: scale(1.2) translate3d(-300px, 300px, 0);
        -moz-transform: scale(1.2) translate3d(-300px, 300px, 0);
      }
    }

html:

<div id="stars">div>