JavaScript教程:Table行定位效果

近来有客户要求用table显示一大串数据，由于滚动后就看不到表头，很不方便，所以想到这个效果。上次做 table排序 对table有了一些了解，这次更是深入了解了一番，发现table原来是这么不简单。

还不清楚这个效果叫什么，有点像表头固定的效果，就叫行定位吧，本来想把列定位也做出来，但暂时还没这个需求，等以后有时间再弄吧。
在 淘宝的商品搜索页 也看到类似的效果，但淘宝的不是table，而是li，而我这个是用在table上的。

要说明一下的是，我这个效果是用在一些普通的产品列表，当数据比较多时提高用户体验，而不是单单做数据显示，跟excel那样的方式是不同的。

效果预览

为方便预览，建议缩小浏览器。

运行代码框
!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"html xmlns="http://www.w3.org/1999/xhtml"headmeta http-equiv="Content-Type" content="text/html; charset=gb2312" /titleJavaScript Table行定位效果/titlescriptvar isIE = (document.all) ？ true : false;var isIE6 = isIE && (navigator.userAgent.indexOf('MSIE 6.0') != -1);var isIE7 = isIE && (navigator.userAgent.indexOf('MSIE 7.0') != -1);var isIE6or7 = isIE6 || isIE7;var isChrome = navigator.userAgent.indexOf('Chrome') != -1;var $ = function (id) {return "string" == typeof id ？ document.getElementById(id) : id;};var Extend = function(destination, source) {for (var property in source) {destination[property] = source[property];}return destination;}var CurrentStyle = function(element){return element.currentStyle || document.defaultView.getComputedStyle(element, null);}var forEach = function(array, callback, thisObject){if(array.forEach){array.forEach(callback, thisObject);}else{for (var i = 0, len = array.length; i len; i++) { callback.call(thisObject, array[i], i, array); }}}var Filter = function(array, callback, thisObject){if(array.filter){return array.filter(callback, thisObject);}else{var res = [];for (var i = 0, len = array.length; i len; i++) { callback.call(thisObject, array[i], i, array) && res.push(array[i]); }return res;}}var Bind = function(object, fun) {var args = Array.prototype.slice.call(arguments).slice(2);return function() {return fun.apply(object, args.concat(Array.prototype.slice.call(arguments)));}}function addEventHandler(oTarget, sEventType, fnHandler) {if (oTarget.addEventListener) {oTarget.addEventListener(sEventType, fnHandler, false);} else if (oTarget.attachEvent) {oTarget.attachEvent("on" + sEventType, fnHandler);} else {oTarget["on" + sEventType] = fnHandler;}};var TableFixed = function(table, options){this._oTable = $(table);//原tablethis._nTable = this._oTable.cloneNode(false);//新tablethis._nTable.id = "";//避免id冲突this._oTableLeft = this._oTableTop = this._oTableBottom = 0;//记录原table坐标参数this._oRowTop = this._oRowBottom = 0;//记录原tr坐标参数this._viewHeight = this._oTableHeight = this._nTableHeight = 0;//记录高度this._nTableViewTop = 0;//记录新table视框topthis._selects = [];//select集合，用于ie6覆盖selectthis._style = this._nTable.style;//用于简化代码//chrome的scroll用document.bodythis._doc = isChrome ？ document.body : document.documentElement;//chrome透明用rgba(0, 0, 0, 0)this._transparent = isChrome ？ "rgba(0, 0, 0, 0)" : "transparent";this.SetOptions(options);this._index = this.options.Index;this._pos = this.options.Pos;this.Auto = !!this.options.Auto;this.Hide = !!this.options.Hide;addEventHandler(window, "resize", Bind(this, this.SetPos));addEventHandler(window, "scroll", Bind(this, this.Run));this._oTable.parentNode.insertBefore(this._nTable, this._oTable);this.Clone();};TableFixed.prototype = {//设置默认属性SetOptions: function(options) {this.options = {//默认值Index:0,//tr索引Auto:true,//是否自动定位Pos:0,//自定义定位位置百分比(0到1)Hide:false//是否隐藏（不显示）};Extend(this.options, options || {});},//克隆表格Clone: function(index) {//设置table样式this._style.width = this._oTable.offsetWidth + "px";this._style.position = isIE6 ？ "absolute" : "fixed";this._style.zIndex = 100;//设置indexthis._index = Math.max(0, Math.min(this._oTable.rows.length - 1, isNaN(index) ？ this._index : index));//克隆新行this._oRow = this._oTable.rows[this._index];var oT = this._oRow, nT = oT.cloneNode(true);if(oT.parentNode != this._oTable){nT = oT.parentNode.cloneNode(false).appendChild(nT).parentNode;}//插入新行if(this._nTable.firstChild){this._nTable.replaceChild(nT, this._nTable.firstChild);}else{this._nTable.appendChild(nT);}//去掉table上面和下面的边框if(this._oTable.border 0){switch (this._oTable.frame) {case "above" :case "below" :case "hsides" :this._nTable.frame = "void"; break;case "" :case "border" :case "box" :this._nTable.frame = "vsides"; break;}}this._style.borderTopWidth = this._style.borderBottomWidth = 0;//设置td样式var nTds = this._nTable.rows[0].cells;forEach(this._oRow.cells, Bind(this, function(o, i){var css = CurrentStyle(o), style = nTds[i].style;//设置td背景style.backgroundColor = this.GetBgColor(o, css.backgroundColor);//设置td的width,没考虑ie8/chrome设scroll的情况style.width = (document.defaultView ？ parseFloat(css.width): (o.clientWidth - parseInt(css.paddingLeft) - parseInt(css.paddingRight))) + "px";}));//获取table高度this._oTableHeight = this._oTable.offsetHeight;this._nTableHeight = this._nTable.offsetHeight;this.SetRect();this.SetPos();},//获取背景色GetBgColor: function(node, bgc) {//不要透明背景（没考虑图片背景）while (bgc == this._transparent && (node = node.parentNode) != document) {bgc = CurrentStyle(node).backgroundColor;}return bgc == this._transparent ？ "#fff" : bgc;},//设置坐标属性SetRect: function() {//用getBoundingClientRect获取原table位置var top = this._doc.scrollTop, rect = this._oTable.getBoundingClientRect();this._oTableLeft = rect.left + this._doc.scrollLeft;this._oTableTop = rect.top + top;this._oTableBottom = rect.bottom + top;//获取原tr位置rect = this._oRow.getBoundingClientRect();this._oRowTop = rect.top + top;this._oRowBottom = rect.bottom + top;},//设置新table位置属性SetPos: function(pos) {//设置posthis._pos = Math.max(0, Math.min(1, isNaN(pos) ？ this._pos : pos));//获取位置this._viewHeight = document.documentElement.clientHeight;this._nTableViewTop = (this._viewHeight - this._nTableHeight) * this._pos;this.Run();},//运行Run: function() {if(!this.Hide){var top = this._doc.scrollTop, left = this._doc.scrollLeft//原tr是否超过顶部和底部,outViewTop = this._oRowTop top, outViewBottom = this._oRowBottom top + this._viewHeight;//原tr超过视窗范围if(outViewTop || outViewBottom){var viewTop = !this.Auto ？ this._nTableViewTop: (outViewTop ？ 0 : (this._viewHeight - this._nTableHeight))//视窗top,posTop = viewTop + top;//位置top//在原table范围内if(posTop this._oTableTop && posTop + this._nTableHeight this._oTableBottom){//定位if(isIE6){this._style.top = posTop + "px";this._style.left = this._oTableLeft + "px";setTimeout(Bind(this, this.SetSelect), 0);//iebug}else{this._style.top = viewTop + "px";this._style.left = this._oTableLeft - left + "px";}return;}}}//隐藏this._style.top = "-99999px";isIE6 && this.ResetSelect();},//设置select集合SetSelect: function() {this.ResetSelect();var rect = this._nTable.getBoundingClientRect();//把需要隐藏的放到_selects集合this._selects = Filter(this._oTable.getElementsByTagName("select"), Bind(this, function(o){var r = o.getBoundingClientRect();if(r.top = rect.bottom && r.bottom = rect.top){o._count ？ o._count++ : (o._count = 1);//防止多个实例冲突//设置隐藏var visi = o.style.visibility;if(visi != "hidden"){ o._css = visi; o.style.visibility = "hidden"; }return true;}}))},//恢复select样式ResetSelect: function() {forEach(this._selects, function(o){ !--o._count && (o.style.visibility = o._css); });this._selects = [];}};/script/headbody style="height:1000px; width:1000px; padding-top:200px;"style type="text/css".tablefixed{width:600px; border-collapse:collapse;}.tablefixed td{ border:5px solid #999; padding:10px;}.tablefixed thead, .tablefixed tfoot{ background:#CCC;}/styletable id="idTableFixed" class="tablefixed"theadtrtd width="50"/tdtd表头/tdtd width="100"/td/tr/theadtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/07/06/1236770.html"图片滑动切换效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/05/23/1205642.html"图片变换效果(ie only)/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/07/21/1247267.html"图片切割效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/09/15/1290954.html"仿LightBox内容显示效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/05/13/1194272.html"图片滑动展示效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/10/20/1314766.html"仿163网盘无刷新文件上传系统/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/11/17/1334778.html"拖放效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/10/05/1303993.html"图片切割系统/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/06/28/1231557.html"自定义多级联动浮动菜单/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/12/24/1360988.html"滑动条效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/12/03/1346386.html"拖拉缩放效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/08/27/1277131.html"渐变效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2008/10/06/1304414.html"Table排序/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2009/01/06/1369979.html"Tween算法及缓动效果/a/tdtd/td/trtrtd/tdtda href="http://www.cnblogs.com/cloudgamer/archive/2009/03/11/1408333.html"颜色梯度和渐变效果/a/tdtd/td/trtfoottrtd/tdtd表尾/tdtd/td/tr/tfoot/tablebr /点击行选择克隆行：当前克隆第 span id="idIndex"1/span 行br /br /input id="idPos" type="button" value="指定中间位置" /input id="idHide" type="button" value="取消定位" /br /br /ps：为方便预览，建议缩小浏览器。scriptvar tf = new TableFixed("idTableFixed");forEach($("idTableFixed").rows, function(o, i){var n = i + 1;o.cells[0].innerHTML = n;o.cells[2].innerHTML = n % 4 ？ " " : "selectoptiontest/option/select";o.onclick = function(){$("idIndex").innerHTML = n; tf.Auto = true; tf.Clone(i);}});tf.Clone();//表格结构修改后应重新Clone一次$("idPos").onclick = function(){tf.Auto = false; tf.SetPos(.5);}$("idHide").onclick = function(){if(tf.Hide){tf.Hide = false;this.value = "取消定位";}else{tf.Hide = true;this.value = "显示定位";}tf.Run();}/script/body/html
[Ctrl+A 全部选择 提示：你可先修改部分代码，再按运行]

注意，使用ie8的兼容性视图会有偏移。

程序原理

一开始的需求只是表头部分在滚动时能一直固定在头部，那关键要实现的就是让tr能定位。首先想到的方法是给tr设置relative，用ie6/7测试以下代码：

!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
html xmlns="http://www.w3.org/1999/xhtml"
body
table cellpadding="5" cellspacing="0" border="1" width="100"
    tr style="position:relative; left:100px;"
        td1/td
        td2/td
    /tr
    tr
        td3/td
        td4/td
    /tr
/table
/body
/html

给tr设置relative后就能相对table定位了，看来很简单啊，但问题是这个方法ie8和ff都无效，而且存在很多问题，所以很快就被抛弃了。
ps：该效果用来做tr的拖动会很方便。

接着想到的是给table插入一个新tr，克隆原来的tr，并设置这个tr为fixed（ie6为absolute），例如：

!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
html xmlns="http://www.w3.org/1999/xhtml"
body
table cellpadding="5" cellspacing="0" border="1" width="100"
    tr style="position:fixed; left:100px;"
        td1/td
        td2/td
    /tr
    tr style="position:absolute; left:200px;"
        td3/td
        td4/td
    /tr
    tr
        td5/td
        td6/td
    /tr
/table
/body
/html

第一个问题是fixed的tr在ie7中不能进行定位，而且td在定位后并不能保持在表格中的布局，这样在原表格插tr就没意义了。
ps：fixed的相关应用可参考仿LightBox效果。

最后我用的方法是新建一个table，并把源tr克隆到新table中，然后通过对新table定位来实现效果。用这个方法关键有两点，首先要做一个仿真度尽可能高的tr，还有是要准确的定位，这些请看后面的程序说明。