js原生拖拽效果 

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        #rect{
            width: 200px;
            height: 200px;
            background: burlywood;
            position: absolute;
            left: 0;
            right: 0;
        }
    </style>
</head>
<body>
    <div id="rect"></div>
</body>
<script>

    // 面条代码 【容易想到】【不易扩展】
    /*var rect = document.getElementById('rect');
    var position;
    var isDrag = false;
    rect.onmousedown = function (e) {
        position = [e.offsetX, e.offsetY];
        isDrag = !isDrag;
        document.onmousemove = function (e) {
            if (isDrag) {
                rect.style.left = e.clientX - position[0] + 'px';
                rect.style.top = e.clientY - position[1] + 'px';
            }
        }
    };
    rect.onmouseup = function () {
        isDrag = !isDrag;
    }*/
    // 构造函数写法  构造对象
    // 抽象化

    // var drag = {
    //     el: '',
    //     isDrag: false,
    //     originX: 12,
    //     originY: 30
    // };
    // drag.__proto__ = {
    //     initOriginPos: function () {},
    //     changeDragStatus: function () {},
    //     bindEvent: function () {},
    //     horizontalMove: function () {},
    //     veticalMove: function () {},
    //     move: function () {},
    // };
    function Drag (el) {
        this.$el = typeof el === 'object' ? el : document.querySelector(el);//判断传入元素，判断是否已经获取，获取后为一个对象
        this.$isDrag = false;//是否拖动，默认不拖动
        this.$originX = undefined;//初始x值，鼠标按压后即获取
        this.$originY = undefined;//初始y值，同上
        this.$currentX = undefined;//鼠标移动后，当前x值
        this.$currentY = undefined;//鼠标移动后，当前y值
        this.bindEvent(this.$el, 'mousedown', this.initOriginPos);//鼠标点击绑定事件，执行函数
        this.bindEvent(document, 'mousemove', this.move);//鼠标移动绑定事件，执行函数
        this.bindEvent(this.$el, 'mouseup', this.changeDragStatus);//鼠标移出绑定事件，执行函数
    }
    //以下为原型方法
    Drag.prototype = {
        initOriginPos: function (event) {
            this.changeDragStatus();
            var ev = event || window.event;//兼容IE浏览器，后者为ie9以下浏览器获取event方式
            this.$originX = event.offsetX;
            this.$originY = event.offsetY;
        },//，从为拖动状态转换为拖动状态，点击时即获取偏移值，通过event属性获取，然后赋值给初始x，y值。
        changeDragStatus: function () {
            this.$isDrag = !this.$isDrag;
        },
        bindEvent: function (ele, type, handle) {
            ele.addEventListener(type, handle.bind(this));
        },
        horizontalMove: function () {
            this.$el.style.left = this.$currentX - this.$originX + 'px';
        },
        verticalMove: function () {
            this.$el.style.top = this.$currentY - this.$originY + 'px';
        },
        move: function (event) {
            if (this.$isDrag) {
                this.$currentX = event.clientX;
                this.$currentY = event.clientY;
                this.horizontalMove();
                this.verticalMove();
            }
        },
    };
var drag=new  Drag("#rect")
</script>
</html>

 

posted @ 2019-08-19 10:22  zhupan  阅读(445)  评论(0)    收藏  举报