JavaScript 实现缓动动画效果详解

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>aninamate动画</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .content {
            width: 1000px;
            margin: 0 auto;
        }
        
        button {
            padding: 5px;
            margin: 60px 10px;
            border: 1px solid #666;
            outline-color: palevioletred;
        }
        
        .both {
            background-color: pink;
            color: #fff;
            background-color: palevioletred;
        }
        
        .box {
            position: relative;
            height: 210px;
            margin: 0px auto;
            background-color: #191b28;
        }
        
        .yutu {
            position: absolute;
            top: 0;
            left: 0;
            width: 180px;
            height: 210px;
        }
        
        .qiaojingjing {
            position: absolute;
            top: 0;
            left: 820px;
            width: 180px;
            height: 210px;
        }
        
        .word1 {
            display: none;
            position: absolute;
            top: -50px;
            left: 45%;
        }
        
        .word2 {
            display: none;
            position: absolute;
            top: -30px;
            left: 50%;
        }
    </style>
</head>

<body>
    <div class="content">
        <button class="btn1">于途前进</button>
        <button class="btn2">乔晶晶前进</button>
        <button class="both">双向奔赴</button>
        <button class="btn3">于途后退</button>
        <button class="btn4">乔晶晶后退</button>
        <div class="box">
            <img src="images/于途.png" alt="" class="yutu">
            <img src="images/乔晶晶.png" alt="" class="qiaojingjing">
            <span class="word1">余生请多指教！</span>
            <span class="word2">余生请多指教！</span>
        </div>
    </div>

    <script>
        var btn1 = document.querySelector('.btn1');
        var btn2 = document.querySelector('.btn2');
        var btn3 = document.querySelector('.btn3');
        var btn4 = document.querySelector('.btn4');
        var both = document.querySelector('.both');
        var yutu = document.querySelector('.yutu');
        var qiaojingjing = document.querySelector('.qiaojingjing');
        var word1 = document.querySelector('.word1');
        var word2 = document.querySelector('.word2');


        btn1.addEventListener('click', function() {
            animate(yutu, 340, function() {
                word1.style.display = 'block';
            });
        });

        btn2.addEventListener('click', function() {
            animate(qiaojingjing, 520, function() {
                word2.style.display = 'block';
            });
        });
        btn3.addEventListener('click', function() {
            animate(yutu, 0, function() {
                word1.style.display = 'none';
            });
        });

        btn4.addEventListener('click', function() {
            animate(qiaojingjing, 820, function() {
                word2.style.display = 'none';
            });
        });

        both.addEventListener('click', function() {
            animate(yutu, 340);
            animate(qiaojingjing, 520);
            word1.style.display = 'block';
            word2.style.display = 'block';

        });


        // 动画函数     obj动画对象, target目标左偏移量, callback回调函数
        function animate(obj, target, callback) {
            // 清除之前的动画
            clearInterval(obj.timer);
            obj.timer = setInterval(function() {
                // 计算出每次移动距离
                var step = (target - obj.offsetLeft) / 20;
                //  步数取整
                step = step > 0 ? Math.ceil(step) : Math.floor(step);
                obj.style.left = obj.offsetLeft + step + 'px';

                if (obj.offsetLeft == target) {
                    // 停止动画
                    clearInterval(obj.timer);
                    // 如果有回调函数，执行回调函数
                    if (callback) {
                        callback();
                    }
                }

            }, 30);
        }
    </script>
</body>

</html>