Learning Web Design Third Edition- P15 ppt

Part II: HTML Markup for Structure
126
1
<map name="veggies" id="veggies">
2
A
<area shape="poly" coords="56,5,45,32,18,32,39,52,30,80,56,64,85,82,76,5
1,97,33,68,31,58,4,55,5" href="peas.html" alt="pea icon" />
B
<area shape="rect" coords="127,9,196,79" href="tomato.html" alt="tomato
icon" />
C
<area shape="circle" coords="270,46,37" href="carrots.html" alt="carrot
icon" />
</map>
3
<p><img src="veggies.gif" width="330" height="90" usemap="veggies"></p>
This marks the beginning of the map. I gave the map the name veggies.
Dreamweaver has used both the name and id attributes to identify the map
element. Both attributes have been included in order to be both backward
(name) and forward (id) compatible. Within the map element there are area
elements representing each hot spot in the image.

2
Each area element has several attributes: the shape identifier (shape),
pixel coordinates (coords), the URL for the link (href), and alternative
text (alt). In this map there are three areas corresponding to the rectangle,
circle, and polygon that I drew over my image:
The list of x,y coordinates for the polygon (poly) identifies each of the
points along the path of the star shape containing a pea.
The x,y pixel coordinates for the rectangle (rect) identify the top-left,

and bottom-right corners of the area over the tomato.
The pixel coordinates for the circle (circle) identify the center point
and the length of the radius for the area with the carrots.

3
The img element now sports the usemap attribute that tells the browser
which map to use (veggies). You can include several imagemapped
images and their respective maps in a single (X)HTML document.
1�
A
B
C
exercise 7-2
|
Making
an imagemap
The image (veggies.gif) shown in this
section and Figure 7-8 is available
in the materials directory for this
chapter.
If you have Dreamweaver, you
can use Figure 7-7 to help make
your own imagemap. The general
steps for making an imagemap are
outlined above, but you’ll need to
consult the documentation for a
detailed explanation of how to use
your program.
Your resulting pixel coordinates
are not likely to be identical to the

ones shown in this chapter because
dragging hotspot areas is not an
exact science. What matters is that
the area is covered well enough
that the user will go to the page as
expected.

veggies.gif
Figure 7-8. Try your hand at making
an imagemap.
exercise 7-2
|
Making
an imagemap
The image (veggies.gif) shown in this
section and Figure 7-8 is available
in the materials directory for this
chapter.
If you have Dreamweaver, you
can use Figure 7-7 to help make
your own imagemap. The general
steps for making an imagemap are
outlined above, but you’ll need to
consult the documentation for a
detailed explanation of how to use
your program.
Your resulting pixel coordinates
are not likely to be identical to the
ones shown in this chapter because
dragging hotspot areas is not an

exact science. What matters is that
the area is covered well enough
that the user will go to the page as
expected.

veggies.gif
Figure 7-8. Try your hand at making
an imagemap.
Test Yourself
Test Yourself
Chapter 7, Adding Images
127
Test Yourself
Images are a big part of the web experience. Answer these questions to see
how well you’ve absorbed the key concepts of this chapter. The correct
answers can be found in Appendix A.
Which two attributes must be included in every img element?

Write the markup for adding an image called furry.jpg that is in the
same directory as the current document.

Why is it necessary to include alternative text? There are two main
reasons.
What is the advantage of including width and height attributes for every
graphic on the page?

What might be going wrong if your images don’t appear when you view
the page in a browser? There are three key explanations.

What does the usemap attribute do?

1.
2.
3.
4.
5.
6.
Part II: HTML Markup for Structure
128
(X)HTML Review: Image and Imagemap Elements
(X)HTML Review:
Image and Imagemap Elements
The following is a summary of the elements we covered in this chapter:
Element and attributes Description
img
Inserts an inline image
src="url"
The location of the image file
alt="text"
Alternative text
width="number"
Width of the graphic
height="number"
Height of the graphic
usemap="usemap"
Indicates a client-side imagemap (preferred)
ismap="ismap"
Indicates a server-side imagemap
longdesc="url"
Points to a document with a long description

of the image
title="text"
Provides a “tool tip” when the user mouses
over the image. Can be used for supplemental
information about the image.
map
Map information for an imagemap
name="text"
The legacy method for giving the map a name
id="text"
The current method for giving the map a
name
area
Contains information for a clickable area in an
imagemap
shape="rect|circle|poly"
Shape of the linked area
coords="numbers"
Pixel coordinates for the linked area
href="url"
Target file for the link
129
IN THIS CHAPTER
How tables are used
Basic table structure
The importance of headers
Spanning rows and columns
Cell padding and spacing
Captions and Summaries
Making tables accessible

Before we launch into the markup for tables, let’s check in with our progress
so far. We’ve covered a lot of territory: how to establish the basic structure
of an (X)HTML document, how to mark up text to give it meaning and
structure, how to make links, and how to add image content to the page.
That’s really the majority of what you need to do for most straightforward
web content.
This chapter and Chapter 9, Forms describe the markup for specialized con-
tent that you might not have a need for right away. Feel free to skip these
chapters and go directly to Chapter 10, Understanding the Standards to learn
more about XHTML, standards compliance, and validation. Or, if you’re get-
ting really antsy to make your pages look good, skip right to Part III and start
playing with Cascading Style Sheets. The tables and forms chapters will be
here when you’re ready for them.
Are you still with me? Great. Let’s talk tables. We’ll start out by reviewing
how tables should be used, then learn the elements used to create HTML
tables. Remember, this is an HTML chapter, so we’re going to focus on the
markup that structures the content into tables, and we won’t be concerned
with how the tables look. Like any web content, the appearance (or presenta-
tion, as we say in the web development world) of tables should be handled
with style sheets.
How Tables Are Used
HTML tables were created for instances when you need to add tabular mate-
rial (data arranged into rows and columns) to a web page. Tables may be used
to organize calendars, schedules, statistics, or other types of information as
shown in Figure 8-1. Note that “data” doesn’t necessarily mean numbers. A
table cell may contain any sort of information, including numbers, text ele-
ments, even images and multimedia objects.
BASIC TABLE
MARKUP
CHAPTER

8
Part II: HTML Markup for Structure
130
Minimal Table Structure
w3.org
lifetimetv.com
mbta.com
Figure 8-1. Examples of tables used for tabular information, such as charts, calendars, and schedules.
In visual browsers, the arrangement of data in rows and columns gives read-
ers an instant understanding of the relationships between data cells and their
respective header labels. Bear in mind when you are creating tables, however,
that some readers will be hearing your data read aloud with a screen reader
or reading Braille output. Later in this chapter, we’ll discuss measures you
can take to make table content accessible to users who don’t have the benefit
of visual presentation.
In the days before style sheets, tables were the only option for creating multi-
column layouts or controlling alignment and white space. Layout tables,
particularly the complex nested table arrangements that were once standard
web design fare, are no longer necessary and are strongly discouraged. See the
sidebar, Using Layout Tables, for more information. This chapter focuses on
(X)HTML tables as they are intended to be used.
Minimal Table Structure
Let’s take a look at a simple table to see what it’s made of. Here is a small table
with three rows and three columns that lists nutritional information.
Menu item Calories Fat
Chicken noodle soup 120 2
Caesar salad 400 26
Figure 8-2 reveals the structure of this table according to the (X)HTML
table model. All of the table’s content goes into cells that are arranged into
rows. Cells contain either header information (titles for the columns, such as

“Calories”) or data, which may be any sort of content.
All of the table’s content
goes into cells that are
arranged into rows.
All of the table’s content
goes into cells that are
arranged into rows.
Minimal Table Structure
Chapter 8, Basic Table Markup
131
header cell
Menu item
data cell
Chicken Soup
data cell
Caesar Salad
header cell
Calories
data cell
120
data cell
400
header cell
Fat (g)
data cell
2
data cell
26
row
row

row
table
Figure 8-2. Tables are made up of rows that contain cells. Cells are the containers for
content.
Simple enough, right? Now let’s look at how those parts translate into
(X)HTML elements (Figure 8-3).
<th>Menu item</th>
<td>Chicken Soup</td>
<td>Caesar Salad</td>
<th>Calories</th>
<td>120</td>
<td>400</td>
<th>Fat (g)</th>
<td>2</td>
<td>26</td>
<tr>
<tr>
<tr>
<table>
</table>
</tr>
</tr>
</tr>
Figure 8-3. The elements that make up the basic structure of a table.
Figure 8-3 shows the elements that identify the table (table), rows (tr, for
“table row”), and cells (th, for “table headers,” and td, for “table data”). Cells
are the heart of the table, because that’s where the actual content goes. The
other elements just hold things together.
What we don’t see are column elements (see note). The number of columns
in a table is determined by the number of cells in each row. This is one of the

things that make (X)HTML tables potentially tricky. Rows are easy—if you
want the table to have three rows, just use three tr elements. Columns are
different. For a table with four columns, you need to make sure that every row
has four td or th elements; the columns are implied.
N o t e
There are two column-related elements in HTML 4.01 and XHTML: col for identi-
fying a column and colgroup for establishing related groups of columns. They were
created to add a layer of information about the table that can potentially speed up
its display, but they are not part of HTML’s row-centric table model. See the sidebar,
Advanced Table Elements, for more information.
Written out in a source document, the markup for the table in Figure 8-3
would look more like the sample below. It is common to stack the th and td
elements in order to make them easier to find in the source. This does not
affect how they are rendered by the browser.
Using Layout Tables
Complex tables were once the
norm for creating interesting web
page layouts, but now that style
sheets offer an alternative, this use
of (X)HTML tables is discouraged.
Not only are they not semantically
sound, but they can be a real
hindrance to accessibility. The
professional web design community
is leaving layout tables in the dust.
If you still choose use table elements
to create the grid of the page, follow
these guidelines:
Use only the minimal table
elements (

table
,
tr
, and
td
).
Avoid nesting tables within
tables.
Avoid tricks like empty rows and
transparent GIF images used
solely for adjusting the spacing.
Use style sheets to control all
presentational aspects of the
table and its contents, such as
colors, alignment, spacing, and
column width.
Make sure that your content still
reads in a logical order in the
source document when all of the
table markup is removed. Tables
that read in a logical order are
said to linearize well. This is the
way visitors with screen readers
will encounter the page.
Layout tables are not necessarily
evil or even inaccessible if handled
responsibly. While we are still in a
period of transition with varying
browser support for CSS layout
features, they are still the choice of

some designers.
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Part II: HTML Markup for Structure
132
Minimal Table Structure
<table>
<tr>
<th>Menu item</th>
<th>Calories</th>
<th>Fat (g)</th>
</tr>
<tr>
<td>Chicken noodle soup</td>
<td>120</td>
<td>2</td>
</tr>
<tr>
<td>Caesar salad</td>
<td>400</td>
<td>26</td>
</tr>
</table>
Remember, all the content for a table must go in cells; that is, within td or
th elements. You can put any content in a cell: text, a graphic, even another
table.
Start and end table tags are used to identify the beginning and end of the

table. The table element may only directly contain some number of tr (row)
elements. The only thing that can go in the tr element is some number of td
or th elements. In other words, there may be no text content within the table
and tr elements that isn’t contained within a td or th.
Finally, Figure 8-4 shows how the table would look in a simple web page, as
displayed by default in a browser. I know it’s not exciting. Excitement hap-
pens in the CSS chapters. What is worth noting is that tables are block-level
elements, so they always start on new lines.
Figure 8-4. The default rendering of our sample table in a browser (Firefox).
Stylin’ Tables
Once you build the structure of the
table in the markup, it’s no problem
adding a layer of style to customize
its appearance.
Style sheets can and should be used
to control these aspects of a table’s
visual presentation. We’ll get to all
the formatting tools you’ll need in
the following chapters:
In Chapter 12, Formatting Text:
Font settings for cell contents
Text color in cells
In Chapter 14, Thinking Inside the
Box:
Table dimensions (width and
height)
Borders
Cell padding (space around cell
contents)
Margins around the table

In Chapter 13, Colors and
Backgrounds:
Background colors
Tiling background images
In Chapter 17, CSS Techniques:
Special properties for controlling
borders and spacing between
cells
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Stylin’ Tables
Once you build the structure of the
table in the markup, it’s no problem
adding a layer of style to customize
its appearance.
Style sheets can and should be used
to control these aspects of a table’s
visual presentation. We’ll get to all
the formatting tools you’ll need in
the following chapters:
In Chapter 12, Formatting Text:
Font settings for cell contents
Text color in cells

In Chapter 14, Thinking Inside the
Box:
Table dimensions (width and
height)
Borders
Cell padding (space around cell
contents)
Margins around the table
In Chapter 13, Colors and
Backgrounds:
Background colors
Tiling background images
In Chapter 17, CSS Techniques:
Special properties for controlling
borders and spacing between
cells
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Minimal Table Structure
Chapter 8, Basic Table Markup
133
The following is the source for another table. Can you tell how many rows
and columns it will have when it is displayed in a browser?

<table>
<tr>
<td>Sufjan Stevens</td>
<td>Illinoise</td>
<td>Asthmatic Kitty Records</td>
</tr>
<tr>
<td>The Shins</td>
<td>Oh Inverted World</td>
<td>Sub-pop Records</td>
</tr>
</table>
If you guessed that it’s a table with two rows and three columns, you’re cor-
rect. Two tr elements create two rows; three td elements in each row create
three columns.
The sample table in this section has been stripped down to its
bare essentials to make its structure clear while you learn how
tables work. It is worth noting, however, that there are other
table elements and attributes that offer more complex semantic
descriptions and improve the accessibility of tabular content. A
thoroughly marked-up version of the sample table might look
like this:
<table summary="A listing of calorie and fat
content for each of the most popular menu items">
<caption>Nutritional Information</caption>
<thead>
<tr>
<th scope="column">Menu item</th>
<th scope="column">Calories</th>
<th abbr="fat" scope="column">Fat (g)</th>

</tr>
</thead>
<tbody>
<tr>
<td>Chicken noodle soup</td>
<td>120</td>
<td>2</td>
</tr>
<tr>
<td>Caesar salad</td>
<td>400</td>
<td>26</td>
</tr>
</tbody>
</table>
Row group elements
You can describe rows or groups of rows as belonging to a
header, footer, or the body of a table using the
thead
,
tfoot
,
and
tbody
elements respectively. Some user agents (another
word for a browsing device) may repeat the header and footer
rows on tables that span multiple pages. Authors may also use
these elements to apply styles to various regions of a table.
Column group elements
Columns may be identified with the

col
element or put into
groups using the
colgroup
element. This is useful for adding
semantic context to information in columns and may be used
to calculate the width of tables more quickly.
Accessibility features
Accessibility features such as captions and summaries for
providing descriptions of table content, and the
scope
and
headers
attributes for explicitly connecting headers with their
respective content are discussed later in this chapter.
An in-depth exploration of the advanced table elements are
beyond the scope of this book, but you may want to do more
research if you anticipate working with data-heavy tables. For
a detailed explanation, see the HTML 4.01 Recommendation at
www.w3.org/TR/REC-html40/struct/tables.html.
Advanced Table Elements
Part II: HTML Markup for Structure
134
Table Headers
Table Headers
As you can see in Figure 8-4, the text marked up as headers (th elements) are
displayed differently from the other cells in the table (td elements). The dif-
ference, however, is not purely cosmetic. Table headers are important because
they provide information or context about the cells in the row or column
they precede. The th element may be handled differently than tds by alterna-

tive browsing devices. For example, screen readers may read the header aloud
before each data cell (“Menu item, Caesar salad, Calories, 400, Fat-g, 26”).
In this way, they are a key tool for making table content accessible. Don’t try
to fake headers by formatting a row of td elements differently than the rest of
the table. Conversely, don’t avoid using th elements because of their default
rendering (bold and centered). Mark up the headers semantically and change
the presentation later with a style rule.
That covers the basics. Before we get more fancy, try your hand at Exercise 8-1.
Spanning Cells
One fundamental feature of table structure is cell spanning, which is the
stretching of a cell to cover several rows or columns. Spanning cells allows
you to create complex table structures, but it has the side effect of making the
markup a little more difficult to keep track of. You make a header or data cell
span by adding the colspan or rowspan attributes, as we’ll discuss next.
Column spans
Column spans, created with the colspan attribute in the td or th element,
stretch a cell to the right to span over the subsequent columns (Figure 8-6).
Here a column span is used to make a header apply to two columns. (I’ve
added a border around cells to reveal the table structure in the screenshot.)
<table>
<tr>
<th colspan="2">Fat</th>
</tr>
<tr>
exercise 8-1
|
Making a simple table
Try writing the markup for the table shown in Figure 8-5. You can open an HTML editor
or just write it down on paper. The finished markup is provided in Appendix A.
(Note, I’ve added a 1-pixel border around cells with a style rule just to make the

structure clear. You won’t include this in your version.)
Be sure to close all table elements. Not only is it required in XHTML and recommended
practice in all HTML documents, some browsers will not display the table at all if the
end table tag (
</table>
) is missing.
exercise 8-1
|
Making a simple table
Try writing the markup for the table shown in Figure 8-5. You can open an HTML editor
or just write it down on paper. The finished markup is provided in Appendix A.
(Note, I’ve added a 1-pixel border around cells with a style rule just to make the
structure clear. You won’t include this in your version.)
Be sure to close all table elements. Not only is it required in XHTML and recommended
practice in all HTML documents, some browsers will not display the table at all if the
end table tag (
</table>
) is missing.
Figure 8-5. Write the markup for this table.
Spanning Cells
Chapter 8, Basic Table Markup
135
<td>Saturated Fat (g)</td>
<td>Unsaturated Fat (g)</td>
</tr>
</table>
Figure 8-6. The colspan attribute stretches a cell to the right to span the specified
number of columns.
Notice in the first row (tr) that there is only one th element, while the second
row has two td elements. The th for the column that was spanned over is no

longer in the source; the cell with the colspan stands in for it. Every row
should have the same number of cells or equivalent colspan values. For
example, there are two td elements and the colspan value is 2, so the implied
number of columns in each row is equal.
Row spans
Row spans, created with the rowspan attribute, work just like column spans,
except they cause the cell to span downward over several rows. In this exam-
ple, the first cell in the table spans down three rows (Figure 8-8).
<table>
<tr>
<th rowspan="3">Serving Size</th>
<td>Small (8oz.)</td>
</tr>
<tr>
<td>Medium (16oz.)</td>
</tr>
<tr>
<td>Large (24oz.)</td>
</tr>
</table>
exercise 8-2
|
Column spans
Try writing the markup for the table shown in Figure 8-7. You can open an HTML
editor or just write it down on paper. Don’t worry if your table doesn’t look exactly
like the one shown here. The rules have been added to reveal the cell structure.
Check Appendix A for the final markup.
Figure 8-7. Practice column spans by writing the markup for this table.
exercise 8-2
|

Column spans
Try writing the markup for the table shown in Figure 8-7. You can open an HTML
editor or just write it down on paper. Don’t worry if your table doesn’t look exactly
like the one shown here. The rules have been added to reveal the cell structure.
Check Appendix A for the final markup.
Figure 8-7. Practice column spans by writing the markup for this table.
Some hints:
For simplicity’s sake, this table uses all
td
elements.
The second row shows you that the
table has a total of three columns.
When a cell is spanned over, its
td

element does not appear in the table.
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Some hints:
For simplicity’s sake, this table uses all
td
elements.
The second row shows you that the
table has a total of three columns.
When a cell is spanned over, its
td

element does not appear in the table.
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WA R N I N G
Be careful with colspan values; if you
specify a number that exceeds the number
of columns in the table, most browsers
will add columns to the existing table,
which typically screws things up.