javascript 拖动表格行实现代码

时间：2021-05-26

行拖动的实现思路非常简单，选中一行，往上拖就与上面的行交换位置，往下拖就与下面的行交换位置。问题是如何得到交换行。我见过一个非常详细的教程，它会把表格里的每一行的高度与Y坐标计算出来，换言之，都时是比较e.pageX是否在[rowTop,rowBottom]区间之内。但这也带来第二个问题，有多少行就有多个这样的区间。于是解法就变成取事件源对象，然后再往上取其父对象，如果其父对象是TR元素，就取其[rowTop,rowBottom]区间....思路非常直接，同时也客观做出一个限制——不能使用代理拖动。先不谈是拖动代理还是拖动实物，光是在移动鼠标的过程要做的计算量就非常大，幸好还在IE的承受范围之内。有更好的方法吗？

人之所以先入为主，因为他就握着这么几把锁匙。如果他手上的锁匙非常多时，他在开门时就会稍微停下来，认真挑选了。因此熟悉掌握越多的原生API就越好，我们就才获取更优的选项。换一个思路，在拖动时（mousedown）保存当前行及其样式与坐标，拖动中取得鼠标所在位置上的元素，这个元素是使用一个巧妙的API取得document.elementFromPoint(x,y)。通常情况，我们取得的是TD，当然如果你在里面塞进一个DIV，那就是DIV罗。然后我们再取得其TR元素，然后比较mousedown时保存的TR元素是不是同一个元素，不是同一个元素，我们才做进一步的操作。这时我们就要判其是向上移向下移，简单的减法而已。接着是交换两行，使用insertBefore。最后当mouseup时，还原行的样式就是！由于没有复杂的坐标计算，整个程式出奇的高效！

完整演示代码

<!doctype html><html> <head> <title>表格行拖动</title> <script> window.onload = function(){ //绑定事件 var addEvent = document.addEventListener ? function(el,type,callback){ el.addEventListener( type, callback, !1 ); } : function(el,type,callback){ el.attachEvent( "on" + type, callback ); } //移除事件 var removeEvent = document.removeEventListener ? function(el,type,callback){ el.removeEventListener( type, callback ); } : function(el,type,callback){ el.detachEvent( "on" + type, callback); } //精确获取样式 var getStyle = document.defaultView ? function(el,style){ return document.defaultView.getComputedStyle(el, null).getPropertyValue(style) } : function(el,style){ style = style.replace(/\-(\w)/g, function($, $1){ return $1.toUpperCase(); }); return el.currentStyle[style]; } var dragManager = { clientY:0, draging:function(e){//mousemove时拖动行 var dragObj = dragManager.dragObj; if(dragObj){ e = e || event; if(window.getSelection){//w3c window.getSelection().removeAllRanges(); }else if(document.selection){ document.selection.empty();//IE } var y = e.clientY; var down = y > dragManager.clientY;//是否向下移动 var tr = document.elementFromPoint(e.clientX,e.clientY); if(tr && tr.nodeName == "TD"){ tr = tr.parentNode dragManager.clientY = y; if( dragObj !== tr){ tr.parentNode.insertBefore(dragObj, (down ? tr.nextSibling : tr)); } }; } }, dragStart:function(e){ e = e || event; var target = e.target || e.srcElement; if(target.nodeName === "TD"){ target = target.parentNode; dragManager.dragObj = target; if(!target.getAttribute("data-background")){ var background = getStyle(target,"background-color"); target.setAttribute("data-background",background) } //显示为可移动的状态 target.style.backgroundColor = "#ccc"; target.style.cursor = "move"; dragManager.clientY = e.clientY; addEvent(document,"mousemove",dragManager.draging); addEvent(document,"mouseup",dragManager.dragEnd); } }, dragEnd:function(e){ var dragObj = dragManager.dragObj if (dragObj) { e = e || event; var target = e.target || e.srcElement; if(target.nodeName === "TD"){ target = target.parentNode; dragObj.style.backgroundColor = dragObj.getAttribute("data-background"); dragObj.style.cursor = "default"; dragManager.dragObj = null; removeEvent(document,"mousemove",dragManager.draging); removeEvent(document,"mouseup",dragManager.dragEnd); } } }, main:function(el){ addEvent(el,"mousedown",dragManager.dragStart); } } var el = document.getElementById("table"); dragManager.main(el); } </script> <style> .table{ width:60%; border: 1px solid red; border-collapse: collapse; } .table td{ border: 1px solid red; height: 20px; } </style> </head> <body> <h1>表格行拖动</h1> <table id="table" class="table"> <tbody> <tr> <td>1</td> <td>One</td> <td>dom.require</td> </tr> <tr id="2" > <td class="2">2</td> <td>Two</td> <td>ControlJS </td> </tr> <tr id="3" > <td class="3">3</td> <td>Three</td> <td>HeadJS</td> </tr> <tr id="4" > <td class="4">4</td> <td>Four</td> <td>LAB.js</td> </tr> <tr id="5" > <td class="5">5</td> <td>Five</td> <td>$script.js</td> </tr> <tr id="6" > <td class="6">6</td> <td>Six</td> <td>NBL.js</td> </tr> </tbody> </table> </body></html>

核心代码

window.onload = function(){ //绑定事件 var addEvent = document.addEventListener ? function(el,type,callback){ el.addEventListener( type, callback, !1 ); } : function(el,type,callback){ el.attachEvent( "on" + type, callback ); } //移除事件 var removeEvent = document.removeEventListener ? function(el,type,callback){ el.removeEventListener( type, callback ); } : function(el,type,callback){ el.detachEvent( "on" + type, callback); } //精确获取样式 var getStyle = document.defaultView ? function(el,style){ return document.defaultView.getComputedStyle(el, null).getPropertyValue(style) } : function(el,style){ style = style.replace(/\-(\w)/g, function($, $1){ return $1.toUpperCase(); }); return el.currentStyle[style]; } var dragManager = { clientY:0, draging:function(e){//mousemove时拖动行 var dragObj = dragManager.dragObj; if(dragObj){ e = e || event;//清除选区 if(window.getSelection){//w3c window.getSelection().removeAllRanges(); }else if(document.selection){ document.selection.empty();//IE } var y = e.clientY; var down = y > dragManager.clientY;//是否向下移动 var tr = document.elementFromPoint(e.clientX,e.clientY); if(tr && tr.nodeName == "TD"){ tr = tr.parentNode dragManager.clientY = y; if( dragObj !== tr){ tr.parentNode.insertBefore(dragObj, (down ? tr.nextSibling : tr)); } }; } }, dragStart:function(e){ e = e || event; var target = e.target || e.srcElement; if(target.nodeName === "TD"){ target = target.parentNode; dragManager.dragObj = target; if(!target.getAttribute("data-background")){ var background = getStyle(target,"background-color"); target.setAttribute("data-background",background) } //显示为可移动的状态 target.style.backgroundColor = "#ccc"; target.style.cursor = "move"; dragManager.clientY = e.clientY; addEvent(document,"mousemove",dragManager.draging); addEvent(document,"mouseup",dragManager.dragEnd); } }, dragEnd:function(e){ var dragObj = dragManager.dragObj if (dragObj) { e = e || event; var target = e.target || e.srcElement; if(target.nodeName === "TD"){ target = target.parentNode; dragObj.style.backgroundColor = dragObj.getAttribute("data-background"); dragObj.style.cursor = "default"; dragManager.dragObj = null; removeEvent(document,"mousemove",dragManager.draging); removeEvent(document,"mouseup",dragManager.dragEnd); } } }, main:function(el){ addEvent(el,"mousedown",dragManager.dragStart); } } var el = document.getElementById("table"); dragManager.main(el);}

实现代码二

<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" > <head > <title>无标题页</title> </head> <body> <table id="tb1" border="1" cellpadding="3"> <tr> <th>移动</th> <th>数据</th> <th>数据</th> <th>数据</th> </tr> <tr> <td>*</td> <td>11111111111</td> <td>sdgergserhserhserh</td> <td>awegaw</td> </tr> <tr> <td>*</td> <td>222222222</td> <td>serherwwwwww</td> <td>fafafff</td> </tr> <tr> <td>*</td> <td>333333333</td> <td>qqqqqqqwewer</td> <td>yukyuk</td> </tr> </table> <script type="text/javascript"> var curTr = null; var tb1 = document.getElementById('tb1'); var trs = tb1.getElementsByTagName('tr'); tb1.onselectstart = function(){ if(curTr){ document.selection.empty(); return true; } }; for(var i=1; i<trs.length; i++) { var tds = trs[i].getElementsByTagName('td'); tds[0].style.cursor = 'move'; tds[0].onmousedown = function(){ curTr = this.parentNode; curTr.style.backgroundColor = '#eff'; }; tds[0].onmouseover = function() { if(curTr && curTr != this.parentNode) { this.parentNode.swapNode(curTr); } } } document.body.onmouseup = function(){ if(curTr){ curTr.style.backgroundColor = ''; curTr = null; } }; </script> </body> </html>

注：不兼容firefox，在IE和chrome下测试通过哦。

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