原生js实现拖拽改变元素顺序
代码展示如下：
<!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{border: 10px solid #000;}.item{margin: 10px 10px 0 10px;background-color: aquamarine;padding: 10px;text-align: center;}.item:nth-last-child(1){margin-bottom: 10px;}</style>
</head>
<body><div class="box"></div><h1></h1><script>class Demo {constructor(data,box,showResBox){this.data = datathis.box = boxthis.showResBox = showResBoxthis.init(data,box,showResBox)}init (data,box) {let fragment = document.createDocumentFragment();for (let i = 0; i < data.length; i++) {let div = document.createElement("div")div.setAttribute("class","item")div.setAttribute("draggable",true)div.innerText = data[i]fragment.appendChild(div)}box.appendChild(fragment)this.showResBox.innerHTML = `最终的结果：${data.join('-')}`this.handledragstart(box)this.handledragover(box)this.handledragend(box)fragment = null}changeElemPosition(source,target,parentNode) {let sourceNext = source.nextSibling;let targetNext = target.nextSibling;parentNode.insertBefore(target,sourceNext)parentNode.insertBefore(source,targetNext)}eventFn(e) {let that = thisswitch (e.type) {case 'dragstart':if (e.target.className=="item") {that.sourceElem = e.target}returncase 'dragover':e.preventDefault()if (e.target.className=="item") {that.targetElem = e.target}returncase 'dragend':let temp = []that.changeElemPosition(that.sourceElem,that.targetElem,e.currentTarget)Array.from(e.currentTarget.children).forEach(elem=>{temp.push(Number(elem.innerText)) })that.data = [...temp]that.showResBox.innerHTML = `最终的结果：${that.data.join('-')}`that.removeEventAndObj(that.eventFn)return}}handledragstart (box) {box.addEventListener('dragstart',(e)=>{this.eventFn(e)})}handledragover (box) {box.addEventListener('dragover',(e)=>{this.eventFn(e)})}handledragend (box) {box.addEventListener('dragend',(e)=>{this.eventFn(e)})}removeEventAndObj(eventFn) {this.targetElem = nullthis.sourceElem = nullthis.box.removeEventListener('dragstart',eventFn)this.box.removeEventListener('dragover',eventFn)this.box.removeEventListener('dragend',eventFn)}}let d = new Demo([1,2,3,4,6],document.querySelector('.box'),document.querySelector('h1'))</script>
</body>
</html>
效果展示如下：
知识点须知：【详情请参考：insertBefore】
Node.insertBefore(newNode,referenceNode)
如果给定的节点（newNode）是对文档中现有节点的引用，insertBefore方法会将其从当前位置移动到新位置（将节点附加到其他节点之前的操作，不需要从其父节点删除该节点）。
用法：
parentNode.insertBefore(newNode, referenceNode);