js 鼠标放到图片上放大某一部分效果

动图效果：

 

 代码：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
            }

            .container,
            img,
            .bigger {
                width: 200px;
                height: 200px;
            }

            .container {
                display: inline-block;
                position: relative;
                background: url(images/1.png) center;
                background-size: contain;
            }

            img {
                position: absolute;
                top: 0;
                left: 0;
            }

            .box {
                width: 100px;
                height: 100px;
                background-color: #ffff7f;
                opacity: 0.7;
                position: absolute;
            }

            .bigger {
                position: relative;
                display: inline-block;
                overflow: hidden;
            }

            .biggerImg {
                position: absolute;
                transform: scale(2);
                transform-origin: top left;
            }
        </style>
    </head>
    <body>
        <div class="container">
            <div class="box" style="top: 0px;left: 0px;"></div>
        </div>
        <div class="bigger">
            <img class="biggerImg" src="./images/1.png" style="display: none;" />
        </div>
    </body>

    <script type="text/javascript">
        var container = document.querySelector(".container");
        var box = document.querySelector(".box");
        var bigger = document.querySelector(".biggerImg");
        var width = box.parentNode.offsetWidth;
        var height = box.parentNode.offsetHeight;


        container.addEventListener("mousedown", function() {
            bigger.style.display = "block";
            container.addEventListener("mousemove", mouseMove);
            container.addEventListener("mouseup", function() {
                bigger.style.display = "none";
                container.removeEventListener("mousemove", mouseMove);
            })
        });

        function mouseMove(e) {
            if (e.clientY - 50 < 0) {
                box.style.top = 0;
                bigger.style.top = 0;
            } else if (e.clientY - 50 > 100) {
                box.style.top = 100;
                bigger.style.top = 100;
            } else {
                box.style.top = e.clientY - 50 + "px";
                bigger.style.top = -2 * (e.clientY - 50) + "px";
            }

            if (e.clientX - 50 < 0) {
                box.style.left = 0;
                bigger.style.left = 0;
            } else if (e.clientX - 50 > 100) {
                box.style.left = 100;
                bigger.style.left = 100;
            } else {
                box.style.left = e.clientX - 50 + "px";
                bigger.style.left = -2 * (e.clientX - 50) + "px";
            }
        }
    </script>
</html>

 

posted @ 2021-12-01 13:52  sunshine233  阅读(331)  评论(0)  编辑  收藏  举报