XHTML 1.0 Element Reference

Table Elements

XHTML table elements are not only a great way to present information, but a useful layout tool as well (see Figure 3.16). XHTML 1.0 expands the table elements in several important ways:

• Support for rendering parts of the frame around a table, rather than "all or nothing."

• Control over which boundaries to draw between cells.

• Table header, body, and footer sections can be defined as separate entities.

Figure 3.16 Tables make complex page layouts such as AltaVista's possible because of the very fine alignment control you have within the table.

<table>

Type:

Container

Function:

Contains all XHTML elements that compose a table.

Syntax:

<table border="thickness_in_pixels"
 width="pixels_or_percentage_of_browser_width"
 cellpadding="pixels" cellspacing="pixels"
 frame="outer_border_rendering" rules="inner_border_rendering"
 summary="description_of_table_contents_and_structure">
...
</table>

Attributes:

The <table> element can take the following attributes to modify how the table is presented:

• border—Specifies the thickness of the table border in pixels.

• cellpadding—Controls the amount of whitespace between the contents of a cell and the edge of the cell.

• cellspacing—Specifies how many pixels of space to leave between individual cells.

• frame—Controls which parts of the table's outer border are rendered. frame can take on the values shown in Table 3.4.

Table 3.4 Values of the frame Attribute of the <table> Element

• rules—Controls which parts of the table's inner borders are displayed. rules can be set equal to one of the values shown in Table 3.5.

Table 3.5 Values of the rules Attribute of the <table> Element

• summary—Provides a synopsis of what's in the table and how the table is structured.

• width—Specifies the width of the table in pixels or as a percentage of the browser screen width.

Example:

<table border="2" cellpadding="4" frame="border"
rules="all" style="align: center">
...
</table>

Related Elements:

The <table> element forms the container for all the other table-related elements. The many elements you can use between <table> and </table> include <caption>, <thead>, <tfoot>, <tbody>, <colgroup>, <col />, <tr>, <th>, and <td>.

<caption>

Type:

Container

Function:

Specifies a caption for a table.

Syntax:

<caption>
... caption text goes here ...
</caption>

Attributes:

None.

Example:

<caption style="align: bottom">
Table 1 - Return on Investment
</caption>

<thead>

Type:

Container

Function:

Defines the header section of a table. Being able to define the header separately enables the browser to duplicate the header when breaking the table across multiple pages.

Syntax:

<thead align="left|center|right|justify|char"
 valign="top|middle|bottom|baseline" char="alignment_character"
 charoff="alignment_character_offset">
... rows that comprise the header ...
</thead>

Attributes:

The <thead> element can take the following four attributes:

• align—Controls the horizontal alignment within the cells of the table header. align can take on values of left, right, center, justify, or char. char is used to align cells by a common character.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• valign—Controls the vertical alignment in the header cells. valign can take on values of top, middle, bottom, or baseline.

Example:

<thead align="center" valign="baseline">
<tr>
<th>id #</th>
<th>property</th>
<th>tax assessment</th>
...
</tr>
</thead>

Related Elements:

The rows of the table header are built with <tr>, <th>, and <td> elements. Each table header must comprise at least one row.

<tfoot>

Type:

Container

Function:

Defines the footer section of the table.

Syntax:

<tfoot align="left|center|right|justify|char"
 valign="top|middle|bottom|baseline" char="alignment_character"
 charoff="alignment_character_offset">
...
</tfoot>

Attributes:

<tfoot> can take the same align and valign attributes as the <thead> element:

• align—Controls the horizontal alignment within the cells of the table footer. align can take on values of left, right, center, justify, or char.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• valign—Controls the vertical alignment in the footer cells. valign can take on values of top, middle, bottom, or baseline.

Example:

<tfoot align="justify" valign="top">
<tr>
<td>&copy; 2000 - Macmillan Computer Publishing USA</td>
...
</tr>
</tfoot>

Related Elements:

You specify the rows and cells in the table footer by using the <tr>, <th>, and <td> elements. A table footer must be made up of at least one row.

<tbody>

Type:

Container

Function:

Defines the body section of the table.

Syntax:

<tbody align="left|center|right|justify|char"
 valign="top|middle|bottom|baseline" char="alignment_character"
 charoff="alignment_character_offset">
...
</tbody>

Attributes:

<tbody> can take the following attributes:

• align—Controls the horizontal alignment within the cells of the table body. align can take on values of left, right, center, justify, and char.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• valign—Controls the vertical alignment in the body cells. valign can take on values of top, middle, bottom, or baseline.

Example:

<tbody align="left" valign="baseline">
<tr>
<td>Red Storm Rising</td>
<td>1500 pages (paperback)</td>
<td>$9.95</td>
...
</tr>
</tbody>

Related Elements:

You specify the rows and cells in the table body by using the <tr>, <th>, and <td> elements. A table body section must contain at least one row.

<colgroup>

Type:

Container

Function:

Groups a set of columns so properties can be assigned to all columns in the group rather than to each one individually.

Syntax:

<colgroup span="number_of_columns" width="width_of_column_group"
 align="left|right|center|justify|char"
 valign="top|middle|bottom|baseline"
 char="alignment_character" charoff="alignment character_offset">
...
</colgroup>

A <colgroup> element has no content or code inside it if the properties put forward in the <colgroup> element are to apply to each column in the group. You can also use the <col/> element inside a <colgroup> element to specify column properties for a subgroup of the larger group.

Attributes:

<colgroup> can take the following attributes:

• align—Controls the horizontal alignment within the column group. align can take on values of left, right, center, justify, or char.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• span—Tells the browser how many columns are in the group. The default value is 1.

• valign—Controls the vertical alignment in the column group. valign can take on values of top, middle, bottom, or baseline.

• width—Specifies how wide (in pixels or in terms of relative width) the enclosed columns should be.

Example:

<colgroup span="3" align="center" valign="top">
</colgroup>
<tr>
<td>Column 1 - center/top alignment</td>
<td>Column 2 - center/top alignment</td>
<td>Column 3 - center/top alignment</td>
<td>Column 4 - default alignment</td>
</tr>

Related Elements:

The <col /> element can be used within the <colgroup> element to refine column properties for a subset of the column group.

<col />

Type:

Standalone

Function:

Specifies properties for a column or columns within a group.

Syntax:

<col span="number_of_columns" width="width_of_column_subgroup"
align="left|right|center|justify"
valign="top|middle|bottom|baseline"
char="alignment_character" charoff="alignment_character_offset" />

Attributes:

<col /> can take the following attributes:

• align—Controls the horizontal alignment within the column cells. align can take on values of left, right, center, justify, or char.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• span—Tells the browser how many columns to which to apply the property. The default value is 1.

• valign—Controls the vertical alignment in the column cells. valign can take on values of top, middle, bottom, or baseline.

• width—Specifies the width (in pixels or in terms of relative width) of the column or column group.

Example:

<table border="1">
<colgroup>
  <col align="center" />
  <col align="right" />
</colgroup>
<colgroup>
  <col align="center" span="2" />
</colgroup>
<tbody>
  <tr>
   <td>First column in first group, center aligned</td>
   <td>Second column in first group, right aligned</td>
   <td>First column in second group, center aligned</td>
   <td>Second column in second group, center aligned</td>
  </tr>
</tbody>
</table>

<tr>

Type:

Container

Function:

Defines a row of a table, table header, table footer, or table body.

Syntax:

<tr align="left|right|center|justify|char"
 valign="top|middle|bottom|baseline"
 char="alignment_character" charoff="alignment_character_offset">
...
</tr>

Attributes specified in a <tr> element apply only to the row that the element is defining and override any default values.

Attributes:

The <tr> element can take the following attributes:

• align—Controls the horizontal alignment within the cells in the row. align can take on values of left, right, center, justify, or char.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• valign—Controls the vertical alignment of the cells in the row. valign can take on values of top, middle, bottom, or baseline.

Example:

<tr style="bgcolor:white" valign="top">
<td>Phone</td>
<td>Extension</td>
<td>Fax</td>
...
</tr>

Related Elements:

Cells in a row are defined using the <td> or <th> elements.

<td>, <th>

Type:

Container

Function:

Defines a cell in a table. <th> creates a header cell whose contents will be rendered in boldface and with a centered horizontal alignment. <td> creates a regular data cell whose contents are aligned flush left and in a normal font weight. Vertical alignment for both types of cells is middle by default.

Syntax:

<td align="left|right|center|justify|char"
 valign="top|middle|bottom|baseline"
 char="alignment_character" charoff="alignment_character_offset"
 rowspan="number_of_rows"
 colspan="number_of_columns"
 abbr="header_cell_abbreviation" axis="list_of_category_names"
 headers="list_of_id headers" scope="row|col|rowgroup|colgroup">

or

<th align="left|right|center|justify|char"
 valign="top|middle|bottom|baseline"
 char="alignment_character" charoff="alignment_character_offset"
 rowspan="number_of_rows"
 colspan="number_of_columns"
 abbr="cell_abbreviation" axis="list_of_category_names"
 headers="list_of_id headers" scope="row|col|rowgroup|colgroup">

Attributes:

Both the <th> and <td> elements can take the following attributes:

• abbr—Specifies an abbreviation form of a cell's contents.

• align—Controls the horizontal alignment within the cell. align can take on values of left, right, center, justify, or char.

• axis—Used to group cells into logical categories.

• char—Specifies the alignment character for when align="char" is used.

• charoff—Prescribes the offset distance from the alignment character.

• colspan—Specifies the number of columns the cell should occupy. The default value is 1.

• headers—Provides a list of IDs of cells that provide header information for the current cell.

• rowspan—Specifies the number of rows the cell should occupy.

• scope—A simpler form of the axis attribute, scope lets you group cells into rows, columns, row groups, or column groups, instead of arbitrarily named logical groups.

• valign—Controls the vertical alignment of the cell. valign can take on values of top, middle, bottom, or baseline.

Example:

<tr valign="bottom">
<th>Column 1 - center/bottom alignment</th>
<td valign="middle">Column 2 - left/middle alignment</td>
<td align="justify">Column 3 - justify/bottom alignment</td>
<td colspan="2">Columns 4 and 5 - left/bottom alignment</td>
</tr>