• 拖拽


    事件绑定 版

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 <head>
     4   <meta charset="UTF-8">
     5   <meta name="viewport" content="width=device-width, initial-scale=1.0">
     6   <title>Document</title>
     7   <style>
     8     #box {
     9        200px;
    10       height: 200px;
    11       background: red;
    12       position: absolute;
    13     }
    14   </style>
    15 </head>
    16 <body>
    17   <div id="box">box</div>
    18   <script>
    19     var oBox = document.querySelector('#box')
    20     oBox.onmousedown = function (e) {
    21       e = e || window.event
    22       // 一旦鼠标按下了,鼠标到div的距离就应该固定下来了,所以要在这里获取
    23       // 获取鼠标到div的顶部和左边的距离
    24       var disX = e.offsetX
    25       var disY = e.offsetY
    26       // move事件写给document,因为只要在box上按下了,在文档中移动都应该触发
    27       document.onmousemove = function (e) {
    28         e = e || window.event
    29         var left = e.clientX - disX
    30         var top = e.clientY - disY
    31         
    32         oBox.style.left = left + 'px'
    33         oBox.style.top = top + 'px'
    34       }
    35       // up事件也写给document,这样鼠标在拖到外面up就也会触发
    36       document.onmouseup = function () {
    37         // 鼠标抬起停止拖拽
    38         document.onmousemove = null
    39       }
    40       // 避免全选文字造成的bug,在这里阻止默认行为
    41       if (e.preventDefault) {
    42         e.preventDefault()
    43       } else {
    44         return false
    45       }
    46     }
    47   </script>
    48 </body>
    49 </html>

    事件监听,限定范围 版

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 <head>
     4   <meta charset="UTF-8">
     5   <meta name="viewport" content="width=device-width, initial-scale=1.0">
     6   <title>Document</title>
     7   <script src="../../utils.js"></script>
     8   <style>
     9     #box {
    10        200px;
    11       height: 200px;
    12       background: red;
    13       position: absolute;
    14     }
    15   </style>
    16 </head>
    17 <body>
    18   <div id="box">box</div>
    19   <script>
    20     var oBox = document.querySelector('#box')
    21     
    23     on(oBox, 'mousedown', function (e) {
    24       // 每次mousedown的时候都要重新计算一下最大值,防止浏览器缩放导致值不准确
    25       var maxLeft = window.innerWidth - oBox.offsetWidth
    26       var maxTop = window.innerHeight - oBox.offsetHeight
    27       e = e || window.event
    28       // 获取鼠标到box的相对坐标
    29       var disX = e.offsetX
    30       var disY = e.offsetY
    31       function move (e) {
    32         e = e || window.event
    33         var top = e.clientY - disY
    34         var left = e.clientX - disX
    35         // 判断
    36         if (top < 0) top = 0
    37         if (top > maxTop) top = maxTop
    38 
    39         if (left < 0) left = 0
    40         if (left > maxLeft) left = maxLeft
    41 
    42         oBox.style.left = left + 'px'
    43         oBox.style.top = top + 'px'
    44       }
    45       on(document, 'mousemove', move)
    46       on(document, 'mouseup', function () {
    47         off(document, 'mousemove', move)
    48       })
    49       // 防止全选文字,阻止默认行为
    50       if (e.preventDefault) {
    51         e.preventDefault()
    52       } else {
    53         return false
    54       }
    55     })
    56   </script>
    57 </body>
    58 </html>
    utils.js代码
     1 const utils = {
     2   /**
     3    * 添加事件监听
     4    * @param ele         <DOMObject> 添加事件的DOM元素
     5    * @param type        <string>    事件类型(不带on)
     6    * @param fn          <function>  事件处理函数
     7    * @param [isCapture] <boolean>   可选参数,是否捕获,true代表捕获,false代表冒泡,默认为false
     8    */
     9   on: function (ele, type, fn, isCapture) {
    10     // 如果参数没有传,默认值为false
    11     if (isCapture === undefined) isCapture = false
    12     if (ele.attachEvent) {
    13       // IE
    14       ele.attachEvent('on' + type, fn)
    15     } else {
    16       ele.addEventListener(type, fn, isCapture)
    17     }
    18   },
    19   /**
    20    * 移出事件监听
    21    * @param ele         <DOMObject> 添加事件的DOM元素
    22    * @param type        <string>    事件类型(不带on)
    23    * @param fn          <function>  事件处理函数
    24    * @param [isCapture] <boolean>   可选参数,是否捕获,true代表捕获,false代表冒泡,默认为false
    25    */
    26   off: function (ele, type, fn, isCapture) {
    27     // 如果参数没有传,默认值为false
    28     if (isCapture === undefined) isCapture = false
    29     if (ele.detachEvent) {
    30       ele.detachEvent('on' + type, fn)
    31     } else {
    32       ele.removeEventListener(type, fn, isCapture)
    33     }
    34   }
    35 }
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  • 原文地址:https://www.cnblogs.com/strongerPian/p/12776476.html
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