原生JS拖拽

2022-11-15 14:44:14 浏览数 (2)

代码语言:javascript复制
<!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>原生JS拖拽</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            position: absolute;
            width: 100px;
            height: 100px;
            background: red;
            cursor: move;
        }
    </style>
</head>

<body>
    <div class="box" id="drag"></div>
</body>

</html>
<script>
    window.onload = function () {
        // 获取拖拽的节点
        let drag = document.getElementById('drag')
        // console.log(drag);
        // 按下别拖拽对象的时候,用drag对象,move和up是全局区域,
        // 也就是整个文档通用,应该使用document对象而不是drag对象。否则,采用drag对象时物体只能往右方或下方移动
        // 鼠标按下时获取到drag对象
        drag.onmousedown = function (event) {
            // console.log(event);
            // 获取window对象
            var event = event || window.event;
            // 鼠标点击物体那一刻相对于物体左侧边框的距离=点击时的位置相对于浏览器最左边的距离-物体左边框相对于浏览器最左边的距离
            let leftX = event.clientX - drag.offsetLeft;
            let leftY = event.clientY - drag.offsetTop;
            // console.log(leftX, leftY);
            // console.log(drag.setCapture);
            if (typeof drag.setCapture !== 'undefined') {
                drag.setCapture();
            }
            document.onmousemove = function (event) {
                var event = event || window.event;
                let moveX = event.clientX - leftX;
                let moveY = event.clientY - leftY;
                // console.log(moveX, moveY);
                if (moveX < 0) {
                    moveX = 0;
                } else if (moveX > window.innerWidth - drag.offsetWidth) {
                    moveX = window.innerWidth - drag.offsetWidth;
                };
                if (moveY < 0) {
                    moveY = 0;
                } else if (moveY > window.innerHeight - drag.offsetHeight) {
                    moveY = window.innerHeight - drag.offsetHeight;
                };
                drag.style.left = moveX   'px';
                drag.style.top = moveY   'px';
            };
            document.onmouseup = function (event) {
                this.onmousemove = null;
                this.onmouseup = null;
                if (typeof drag.releaseCapture != 'undefined') {
                    drag.releaseCapture();
                }
            }
        }
    }
</script>

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