首頁 > 開發者 > JavaScript
行拖動的實現思路非常簡單，選中一行，往上拖就與上面的行交換位置，往下拖就與下面的行交換位置。問題是如何得到交換行。我見過一個非常詳細的教程，它會把表格裡的每一行的高度與Y座標計算出來，換言之，都時是比較e.pageX是否在[rowTop,rowBottom]區間之內。但這也帶來第二個問題，有多少行就有多個這樣的區間。於是解法就變成取事件來源對象，然後再往上取其父物件，如果其父物件是TR元素，就取其[rowTop,rowBottom]區間....思路非常直接，同時也客觀做出一個限制——不能使用代理拖動。先不談是拖動代理還是拖動實物，光是在移動滑鼠的過程要做的計算量就非常大，幸好還在IE的承受範圍之內。有更好的方法嗎？
人之所以先入為主，因為他就握著這麼幾把鎖匙。如果他手上的鎖匙非常多時，他在開門時就會稍微停下來，認真挑選了。因此熟悉掌握越多的原生API就越好，我們就才擷取更優的選項。換一個思路，在拖動時（mousedown）儲存當前行及其樣式與座標，拖動中取得滑鼠所在位置上的元素，這個元素是使用一個巧妙的API取得document.elementFromPoint(x,y)。通常情況，我們取得的是TD，當然如果你在裡面塞進一個DIV，那就是DIV羅。然後我們再取得其TR元素，然後比較mousedown時儲存的TR元素是不是同一個元素，不是同一個元素，我們才做進一步的操作。這時我們就要判其是向上移向下移，簡單的減法而已。接著是交換兩行，使用insertBefore。最後當mouseup時，還原行的樣式就是！由於沒有複雜的座標計算，整個程式出奇的高效！
完整示範代碼
<!doctype html><html> <head> <title>表格行拖動</title> <script> window.onload = function(){ //綁定事件 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); } //精確擷取樣式 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時拖動行 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;//是否向下移動 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) } //顯示為可移動的狀態 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>表格行拖動</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>
核心代碼
window.onload = function(){ //綁定事件 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); } //精確擷取樣式 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時拖動行 var dragObj = dragManager.dragObj; if(dragObj){ e = e || event;//清除選區 if(window.getSelection){//w3c window.getSelection().removeAllRanges(); }else if(document.selection){ document.selection.empty();//IE } var y = e.clientY; var down = y > dragManager.clientY;//是否向下移動 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) } //顯示為可移動的狀態 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);}
實現代碼二
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" > <head > <title>無標題頁</title> </head> <body> <table id="tb1" border="1" cellpadding="3"> <tr> <th>移動</th> <th>資料</th> <th>資料</th> <th>資料</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>
註：不相容firefox，在IE和chrome下測試通過哦。
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
