基于匀速运动的实例讲解(侧边栏,淡入淡出)(3)

日期：2020-05-12 栏目：程序人生 浏览：次

再来一个淡入淡出的效果:

当鼠标移上去之后，透明度变成1

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>淡入淡出 - by ghostwu</title>
  <style>
    img {
      border: none;
      opacity: 0.3;
      filter: alpha(opacity:30);
    }
  </style>
  <script>
    window.onload = function () {
      var timer = null;
      var oImg = document.getElementById("img");
      oImg.onmouseover = function(){
        animate( this, 100, 10 );
      }
      oImg.onmouseout = function(){
        animate( this, 30, -10 );
      }
      //alpha=30 --> 100
      function animate(obj, target, speed) {
        clearInterval(timer);
        var cur = 0;
        timer = setInterval(function () {
          cur = css( obj, 'opacity') * 100;
          if( cur == target ){
            clearInterval( timer );
          }else {
            cur += speed;
            obj.style.opacity = cur / 100;
            obj.style.filter = "alpha(opacity:" + cur + ")";
          }
        }, 30);
      }

      function css(obj, attr) {
        if (obj.currentStyle) {
          return obj.currentStyle[attr];
        } else {
          return getComputedStyle(obj, false)[attr];
        }
      }
    }
  </script>
</head>
<body>
<img src="./img/h4.jpg" alt="" id="img"/>
</body>
</html>

以上这篇基于匀速运动的实例讲解(侧边栏,淡入淡出)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持黑区网络。