HTML table cellspacing and cellpadding in CSS

As I often find myself cleaning up legacy webapp codebases, this item seems pretty common, particularly for sites that were using TABLE based layouts.


<table cellpadding="0" cellspacing="0">
<thead>
<tr><th>Hello</th></tr>
</thead>
<tbody>
<tr><td>World</td></tr>
</tbody>

With modern browsers, this is easily accomplished with some simple CSS, as you might need some distinction between different tables or have some cases that require padding or spacing, you MIGHT consider assigning a CSS class as I have below.


<style type="text/css">
table.modern{
border-collapse: collapse; /* 'cellspacing=0' equivalent */
}
table.modern td,
table.modern th{
padding: 0; /* 'cellpadding=0' equivalent */
}
</style>

<table class="modern">
<thead>
<tr><th>Hello</th></tr>
</thead>
<tbody>
<tr><td>World</td></tr>
</tbody>

Replacing deprecated use of HTML ‘nobr’ tags and ‘nowrap’ attributes

It’s not uncommon to find yourself working on applications that were often build before the widespread adoption of CSS. Alongside legacy <table> based designs, the use of various mechanisms to prevent word-wrapping are often implemented.

I’ve found that the following allows for low-risk transition between technologies…

<style type="text/css">
table.nobr tr th, table tr.nobr th, table tr th.nobr, table thead.nobr tr td, table tbody.nobr tr td,
table.nobr tr td, table tr.nobr td, table tr td.nobr, table thead.nobr tr td, table tbody.nobr tr td,
.nobr {white-space:nowrap;}
</style>

With the above approach, you can apply class="nobr" to any element directly, for <table>‘s I’ve taken it a little further and allowed for the class to be set at various levels in the heirarchy to fill various needs.

MSIE Table styling of empty cells

This one had me stumped for some time, when a table contained either a <td></td> or <th></th> without content the cell would not be properly styled, often lacking borders. Traditionally the solution I used was to insure that all table cells had at least a single space within them so that they would be styled properly in MSIE.

There’s a simpler solution, the below CSS changes the default behavior so that the traditional ‘hack’ is no longer required:


table {
border-collapse:collapse;
empty-cells:show;
}

REFERENCES:

Clientside sorting of HTML TABLE in JavaScript

To save network bandwidth and server resources, it is often beneficial to to sorting of tabular data on the client. Here’s a workable solution that I’ve implemented several times.

Additionally, the need to make the solution ‘accessible’ to screen-reader technology and be backward compatible for users without JavaScript often become challenging.

There are some small “quirks” that you should be aware of…

  • The ‘sortTable’ method uses the ID of the ‘TBODY’. Working to remove this requirement through better use of the DOM.
  • Will likely rework this to use Prototype framework which should result in smaller code.
  • Future enhancement will add a class to the header indicating the sort order of the column(s).
  • Creating the ‘SPAN’ for dates to be sorted is best handled by a taglib.
  • Large TABLE’s can take a significant amount of time to sort on a client, so it’s sometimes better to use a server side solution. Developers should use their experience to make this judgment call.

Example code (XHTML logic removed as usual for brevity):

<html>
<head>
<title>Client Side TABLE sorting</title>
<style type=”text/css”>
/* SCROLL */
div.scroll {width:100%;overflow:scroll;}
html>body div.scroll {width:100%;overflow:scroll} /* fixes IE6 hack */
/*** TABULAR ***/
tr.even {background-color:#eee;}
th.first, td.first {border-width:0;}
th.memo {text-align:left;padding:0;}
td.sorted {background-color: #f0f0f0;}
th.sorted {background-color: #99f;}
tr.even td.sorted { background-color: #d0d0d0; }
table.sorted tr.error { background-color:red; }
table.sorted tr.scroll th { background-color:#99f; text-align:left;}
table.sorted tr.scroll th a.sorted { color:#fff; text-decoration:none;}
table.sorted tr.scroll th a.sorted:hover { color:#fff; text-decoration:underline;}
</style>
<script type=”text/javascript”>
//—————————————————————————–
// sortTable(id, col, rev,xcase)
//
// id – ID of the TABLE, TBODY, THEAD or TFOOT element to be sorted.
// col – Index of the column to sort, 0 = first column, 1 = second column, etc.
// rev – If true, the column is sorted in reverse (descending) order initially.
// xcase – makes sort NOT case sensitive.
//
// The following is an example of jsp code for setting up the reformatted copy of a date
// field to allow sorting by date:
//
// <fmt:formatDate var=”varSortDate” value=”${searchResult.dateOfBirth}” pattern=”${sortableDateTimePattern}” />
// <span title=”<c:out value=”${varSortDate}” />”><fmt:formatDate value=”${searchResult.dateOfBirth}” pattern=”${dateFormatPattern}” /></span> | etc.
//
// The above code creates html code that contains, for example, a line like the following:
//
// <span title=”19640101000000″>01/01/1964</span>
//
// This sort routing concatenates the title element and the text node
// content to sort on the following string:
//
// 1964010100000001/01/1964
//
// This effective ignores the date containing slashes and used the yyyyMMdd etc. value.
// Fields that are not dates should not use the span element and title attribute, unless
// it is desired to sort on something other than the text node content.
//—————————————————————————–
function sortTable(id, col, rev, xcase) {
// Get the table or table section to sort.
var tblEl = xgetHelper(id);
if(tblEl != null){
// The first time this function is called for a given table, set up an array of reverse sort flags.
if (tblEl.reverseSort == null) {
tblEl.reverseSort = new Array();
// Also, assume the column zero is initially sorted.
tblEl.lastColumn = 0; // was 1
}

// If this column has not been sorted before, set the initial sort direction.
if (tblEl.reverseSort[col] == null)
tblEl.reverseSort[col] = rev;

// If this column was the last one sorted, reverse its sort direction.
if (col == tblEl.lastColumn)
tblEl.reverseSort[col] = !tblEl.reverseSort[col];

// Remember this column as the last one sorted.
tblEl.lastColumn = col;
// Set the table display style to “none” – necessary for Netscape 6 browsers.
var oldDsply = tblEl.style.display;
tblEl.style.display = “none”;
// Sort the rows based on the content of the specified column using a selection sort.

var tmpEl;
var i, j;
var minVal, minIdx;
var testVal;
var cmp;
for (i = 0; i < tblEl.rows.length – 1; i++) {

// Assume the current row has the minimum value.
minIdx = i;
minVal = getTextValue(tblEl.rows[i].cells[col], xcase);

// Search the rows that follow the current one for a smaller value.
for (j = i + 1; j < tblEl.rows.length; j++) {
testVal = getTextValue(tblEl.rows[j].cells[col], xcase);
cmp = compareValues(minVal, testVal);
// Negate the comparison result if the reverse sort flag is set.
if (tblEl.reverseSort[col])
cmp = -cmp;
// If this row has a smaller value than the current minimum, remember its
// position and update the current minimum value.
if (cmp > 0) {
minIdx = j;
minVal = testVal;
}
}

// By now, we have the row with the smallest value. Remove it from the
// table and insert it before the current row.
if (minIdx > i) {
tmpEl = tblEl.removeChild(tblEl.rows[minIdx]);
tblEl.insertBefore(tmpEl, tblEl.rows[i]);
}
}

// Make it look pretty.
makePretty(tblEl, col);

// Restore the table’s display style.
tblEl.style.display = oldDsply;
}

return false;
}

//—————————————————————————–
// Functions to get and compare values during a sort.
//—————————————————————————–

// This code is necessary for browsers that don’t reflect the DOM constants
// (like IE).
if (document.ELEMENT_NODE == null) {
document.ELEMENT_NODE = 1;
document.TEXT_NODE = 3;
}

function getTextValue(el, xcase){
var i;
var s;
var spanTitleValue;

// Find and concatenate the values of all text nodes contained within the element.
s = “”;

for (i = 0; i < el.childNodes.length; i++) {
if (el.childNodes[i].nodeType == 1) {
if (el.childNodes[i].nodeName != null) {
if (el.childNodes[i].nodeName == “SPAN”) {
spanTitleValue = el.childNodes[i].getAttribute(“Title”);
s += spanTitleValue;
}
}
else {
}
// Use recursion to get text within sub-elements.
s += getTextValue(el.childNodes[i]);
}
else if (el.childNodes[i].nodeType == document.TEXT_NODE) {
s += el.childNodes[i].nodeValue;
}
else {
// Gets here when element is empty! <span title=””></span>
//alert(‘Error — Not element or text node’);
}
}
return normalizeString(s, xcase);
}

function compareValues(v1, v2) {

var f1, f2;
// If the values are numeric, convert them to floats.

f1 = parseFloat(v1);
f2 = parseFloat(v2);
if (!isNaN(f1) && !isNaN(f2)) {
v1 = f1;
v2 = f2;
}

// Compare the two values.
if (v1 == v2)
return 0;
if (v1 > v2)
return 1
return -1;
}

// Regular expressions for normalizing white space.
var whtSpEnds = new RegExp(“^\\s*|\\s*$”, “g”);
var whtSpMult = new RegExp(“\\s\\s+”, “g”);

function normalizeString(s, xcase) {

s = s.replace(whtSpMult, ” “); // Collapse any multiple whites space.
s = s.replace(whtSpEnds, “”); // Remove leading or trailing white space.

var rc = s;
if(xcase == true) {
rc = s.toUpperCase();
}
return rc;
}

//—————————————————————————–
// Functions to update the table appearance after a sort.
//—————————————————————————–

// Style class names.
var rowClsNm = “even”;
var colClsNm = “sorted”;

// Regular expressions for setting class names.
var rowTest = new RegExp(rowClsNm, “gi”);
var colTest = new RegExp(colClsNm, “gi”);

function makePretty(tblEl, col) {
var i, j;
var rowEl, cellEl;

// Set style classes on each row to alternate their appearance.
for (i = 0; i < tblEl.rows.length; i++) {
rowEl = tblEl.rows[i];
rowEl.className = rowEl.className.replace(rowTest, “”);
if (i % 2 != 0)
rowEl.className += ” ” + rowClsNm;
rowEl.className = normalizeString(rowEl.className);
// Set style classes on each column (other than the name column) to
// highlight the one that was sorted.
for (j = 0; j < tblEl.rows[i].cells.length; j++) { /* was j=2 */
cellEl = rowEl.cells[j];
cellEl.className = cellEl.className.replace(colTest, “”);
if (j == col)
cellEl.className += ” ” + colClsNm;
cellEl.className = normalizeString(cellEl.className);
}
}

// Find the table header and highlight the column that was sorted.
var el = tblEl.parentNode.tHead;
rowEl = el.rows[el.rows.length – 1];
// Set style classes for each column as above.
for (i = 2; i < rowEl.cells.length; i++) {
cellEl = rowEl.cells[i];
cellEl.className = cellEl.className.replace(colTest, “”);
// Highlight the header of the sorted column.
if (i == col)
cellEl.className += ” ” + colClsNm;
cellEl.className = normalizeString(cellEl.className);
}
}
function xgetHelper(id){
var obj = null;
try {
obj = document.getElementById(id);
} catch(z) {
//var dummy=alert(“Error:” + z);
}
return obj;
}
</script>
</head>
<body>
<fieldset>
<div id=”ex_div” class=”scroll”>
<table summary=”” id=”names” class=”sorted” cellspacing=”0″>
<colgroup>
<col style=”first labels” />
<col style=”form_fields” />
</colgroup>
<thead>
<tr class=”scroll”>
<th scope=”col” id=”ex_0″><a href=”javascript:void(0);” class=”sorted” onclick=”return sortTable(‘ex_sort’,0,true,true);”>Alpha</a></th>
<th scope=”col” id=”ex_1″><a href=”javascript:void(0);” class=”sorted” onclick=”return sortTable(‘ex_sort’,1,true,true);”>Date</a></th>
<th scope=”col” id=”ex_2″><a href=”javascript:void(0);” class=”sorted” onclick=”return sortTable(‘ex_sort’,2,true,true);”>Url</a></th>
</tr>
</thead>
<tbody class=”scroll” id=”ex_sort”>
<tr class=”even”>
<td headers=”ex_0″>Alpha</td>
<td headers=”ex_1″><span title=”20070701″>July 2, 2007</span></td>
<td headers=”ex_2″><a href=”javascript:void(0);” onclick=”alert(‘view.php?userid=6’);”>5</a></td>
</tr>
<tr class=”odd”>
<td headers=”ex_0″>Bravo</td>
<td headers=”ex_1″><span title=”20050903″>Sept 3, 2005</span></td>
<td headers=”ex_2″><a href=”javascript:void(0);” onclick=”alert(‘view.php?userid=8’);”>4</a></td>
</tr>
<tr class=”even”>
<td headers=”ex_0″>Charlie</td>
<td headers=”ex_1″><span title=”19700709″>July 9, 1970</span></td>
<td headers=”ex_2″><a href=”javascript:void(0);” onclick=”alert(‘view.php?userid=4’);”>2</a></td>
</tr>
<tr class=”odd”>
<td headers=”ex_0″>Delta</td>
<td headers=”ex_1″><span title=”20001213″>Dec. 13, 2000</span></td>
<td headers=”ex_2″><a href=”javascript:void(0);” onclick=”alert(‘view.php?userid=5’);”>3</a></td>
</tr>
<tr class=”even”>
<td headers=”ex_0″>Echo</td>
<td headers=”ex_1″><span title=”20010911″>Sept 11, 2001</span></td>
<td headers=”ex_2″><a href=”javascript:void(0);” onclick=”alert(‘view.php?userid=2’);”>1</a></td>
</tr>
</tbody>
</table>
</div>
</fieldset>
</body>
</html>

Cheers!