1. HTML5 拖拽
1.1 相关知识
拖拽元素:可以为元素添加来让元素能够被拖拽。
拖拽元素的事件监听:(应用于拖拽元素)
- 当拖拽开始时调用
- 当鼠标离开拖拽元素时调用
- 当拖拽结束时调用
- 整个拖拽过程都会调用
目标元素:把元素A拖拽到元素B里,那么元素B就是目标元素。页面中任何一个元素都可以成为目标元素。
目标元素的事件监听:(应用于目标元素)
- 当拖拽元素进入时调用
- 当拖拽元素停留在目标元素上时,就会连续一直触发(不管拖拽元素此时是移动还是不动的状态)
- 当在目标元素上松开鼠标时调用
- 当鼠标离开目标元素时调用
如果想让拖拽元素在目标元素里做点事情,就必须要在里加这一行代码。
1.2 拖拽基础
- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8" />
- <meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <title>Document</title>
- <style>
- .box {
- width: 200px;
- height: 200px;
- background: green;
- }
- .box2 {
- position: relative;
- left: 300px;
- top: 50px;
- width: 300px;
- height: 300px;
- background: red;
- }
- </style>
- </head>
- <body>
- <div class="box" draggable="true"></div>
- <div class="box2"></div>
- <script>
- // HTML5 拖拽
- // 应用于拖拽元素
- var box = document.querySelector('.box')
- box.ondragstart = function () {
- console.log('拖拽开始')
- }
- box.ondragleave = function () {
- console.log('鼠标离开元素')
- }
- box.ondragend = function () {
- console.log('拖拽结束')
- }
- // box.ondrag = function () {
- // console.log('在拖拽');
- // }
- // 应用于目标元素(想把 box 拖拽进去的地方)
- var box2 = document.querySelector('.box2')
- box2.ondragenter = function () {
- console.log('进来了')
- }
- box2.ondragleave = function () {
- console.log('离开了')
- }
- // 当拖拽元素在 目标元素上时,连续触发
- box2.ondragover = function (e) {
- // 如果想让拖拽元素在目标元素里做点事情,就必须要在 ondragover() 里加event.preventDefault()这一行代码。
- e.preventDefault()
- console.log('over')
- }
- box2.ondrop = function () {
- console.log('松开鼠标了')
- }
- </script>
- </body>
- </html>
复制代码 1.3 将 A 在 B、C 之间拖拽
- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8" />
- <meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <title>Document</title>
- <style>
- .box-b {
- width: 250px;
- height: 250px;
- background: green;
- }
- .cell-a {
- float: left;
- width: 50px;
- height: 50px;
- margin: 5px;
- text-align: center;
- line-height: 50px;
- border-radius: 50%;
- background: red;
- }
- .box-c {
- width: 200px;
- height: 200px;
- margin-top: 10px;
- background: skyblue;
- }
- </style>
- </head>
- <body>
- <p>boxB</p>
- <div class="box-b">
- <div class="cell-a" draggable="true">1</div>
- <div class="cell-a" draggable="true">2</div>
- <div class="cell-a" draggable="true">3</div>
- <div class="cell-a" draggable="true">4</div>
- <div class="cell-a" draggable="true">5</div>
- </div>
- <p>boxC</p>
- <div class="box-c"></div>
- <script>
- var cellA = document.querySelectorAll('.cell-a')
- var boxB = document.querySelector('.box-b')
- var boxC = document.querySelector('.box-c')
- var temp = null
- cellA.forEach((cell, index) => {
- // 从 boxB 拖拽到 boxC
- cell.ondragstart = function () {
- // 保持当前拖拽的元素
- temp = this
- }
- cell.ondragend = function () {
- temp = null
- }
- boxC.ondragover = function (e) {
- e.preventDefault()
- }
- boxC.ondragenter = function () {
- this.appendChild(temp)
- }
- // 从 boxC 拖拽到 boxB
- boxB.ondragover = function (e) {
- e.preventDefault()
- }
- boxB.ondragenter = function () {
- this.appendChild(temp)
- }
- })
- </script>
- </body>
- </html>
复制代码 效果展示
2. 用 js 实现拖拽
2.1 js 简单拖拽
按下鼠标进行简单的拖拽。- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8" />
- <meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <title>Document</title>
- <style>
- #box {
- position: absolute;
- width: 200px;
- height: 200px;
- background: green;
- }
- </style>
- <script>
- window.onload = function () {
- var box = document.getElementById('box')
- var disX = 0
- var disY = 0
- box.onmousedown = function (e) {
- var e = e || window.event
- disX = e.clientX - this.offsetLeft
- disY = e.clientY - this.offsetTop
- box.onmousemove = function (e) {
- var e = e || window.event
- box.style.left = e.clientX - disX + 'px'
- box.style.top = e.clientY - disY + 'px'
- }
- box.onmouseup = function (e) {
- console.log('end')
- this.onmousemove = null
- }
- return false
- }
- }
- </script>
- </head>
- <body>
- <div id="box"></div>
- </body>
- </html>
复制代码 效果展示
2.2 带效果的拖拽
- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8" />
- <meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <title>Document</title>
- <style>
- .box {
- position: absolute;
- width: 200px;
- height: 200px;
- background: skyblue;
- }
- .box1 {
- position: absolute;
- border: 1px dashed black;
- opacity: 0.5;
- }
- .way-box {
- position: absolute;
- bottom: 30px;
- right: 30px;
- /* 无法选中 */
- -moz-user-select: none; /* 火狐 */
- -webkit-user-select: none; /* 谷歌 */
- -ms-user-select: none; /* IE */
- user-select: none;
- }
- </style>
- <script>
- window.onload = function () {
- ;(function () {
- var box = document.querySelector('.box')
- var disX, disY, temp
- var body = document.querySelector('body')
- var way1 = document.querySelector('#way1')
- var way2 = document.querySelector('#way2')
- box.onmousedown = function (e) {
- var e = e || window.event // 兼容性写法
- disX = e.clientX - this.offsetLeft
- disY = e.clientY - this.offsetTop
- temp = document.createElement('div')
- body.appendChild(temp)
- temp.classList.add('box')
- temp.classList.add('box1')
- // 移动后位置会变,temp 的位置应该与 box 位置重合
- temp.style.left = e.clientX - disX + 'px' // 记得加单位!
- temp.style.top = e.clientY - disY + 'px'
- temp.onmousemove = function (e) {
- var e = e || window.event
- temp.style.left = e.clientX - disX + 'px' // 记得加单位!
- temp.style.top = e.clientY - disY + 'px'
- }
- temp.onmouseup = function (e) {
- console.log('end')
- this.onmousemove = null
- // 1 则默认不发生实际移动
- if (way2.checked) {
- box.style.left = e.clientX - disX + 'px'
- box.style.top = e.clientY - disY + 'px'
- }
- temp.style.display = 'none'
- this.onmouseup = null
- }
- }
- })()
- }
- </script>
- </head>
- <body>
- <div class="box"></div>
- <div class="way-box">
- <p>请选择拖拽的方式</p>
- <input type="radio" id="way1" name="way" checked />
- <label for="way1">1</label>
- <input type="radio" id="way2" name="way" />
- <label for="way2">2</label>
- </div>
- </body>
- </html>
复制代码 效果展示
有时会卡顿,未解决…
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