js实现鼠标图片放大缩小

js实现鼠标图片放大缩小

<!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>Document</title>
</head>

<body>
    <img id="img" src="http://blog.aoxuelingshuang.com/ico/log.png?v=1.0.0.5" alt="" style="width: 100px;">
    <script>
        const img = document.querySelector('#img');
        RotateWheel(img);
        function RotateWheel(el) {
            document.onwheel = (e) => {
                let delta = (e.wheelDelta && (e.wheelDelta > 0 ? 1 : -1));
                if (delta > 0) {//放大
                    // 向上滚
                    let oWidth = el.offsetWidth;//取得图片的实际宽度
                    let oHeight = el.offsetHeight; //取得图片的实际高度

                    el.style.width = (oWidth + 50) + "px"
                    el.style.height = (oHeight + 50 / oWidth * oHeight) + "px"

                } else if (delta < 0) {//缩小
                    //向下滚
                    let oWidth = el.offsetWidth; //取得图片的实际宽度
                    let oHeight = el.offsetHeight; //取得图片的实际高度
                    if (el.offsetWidth > 100 || el.offsetHeight > 75) {//判断如果图片缩小到原图大小就停止缩小(100和75分别为原图的宽高)

                        el.style.width = oWidth - 50 + "px"
                        el.style.height = oHeight - 50 / oWidth * oHeight + "px"
                    }
                }
            }
        }
    </script>
</body>

</html>

当页面有滚动条时，放大缩小图片页面会抖动可以禁用滚动条

const body = document.querySelector('body');
body.style.overflow = 'hidden';

 

posted @ 2022-11-14 14:00  默永  阅读(695)  评论(0)  编辑  收藏  举报