What is the World Wide
Web?
- The World
Wide Web (WWW) is most often called the Web.
- The Web is
a network of computers all over the world.
- All the
computers in the Web can communicate with each
other.
- All the
computers use a communication standard called
HTTP.
How does
the WWW work?
- Web
information is stored in documents called Web
pages.
- Web pages
are files stored on computers called Web
servers.
- Computers
reading the Web pages are called Web clients.
- Web
clients view the pages with a program called a Web
browser.
- Popular
browsers are Internet Explorer and Netscape
Navigator.
How does
the browser fetch the pages?
- A browser
fetches a Web page from a server by a request.
- A request
is a standard HTTP request containing a page
address.
- A page
address looks like this:
http://www.someone.com/page.htm.
How does
the browser display the pages?
- All Web
pages contain instructions on how to be
displayed.
- The
browser displays the page by reading these
instructions.
- The most
common display instructions are called HTML
tags.
- HTML tags
look like this <p>This is a
Paragraph</p>.
What is an
HTML File?
- HTML
stands for Hyper Text Markup Language
- An HTML
file is a text file containing small markup
tags
- The markup
tags tell the Web browser how to display the
page
- An HTML
file must have an htm or html file extension
- An HTML
file can be created using a simple text editor
Do You
Want to Try It?
If you are
running Windows, start Notepad (or start SimpleText if
you are on a Mac) and type in the following
text:
<html>
<head>
<title>Title of page</title>
</head>
<body>
This is my first homepage. <b>This text is bold</b>
</body>
</html> |
Save the file
as "mypage.htm".
Start your
Internet browser. Select "Open" (or "Open Page") in the
File menu of your browser. A dialog box will appear.
Select "Browse" (or "Choose File") and locate the HTML
file you just created - "mypage.htm" - select it and
click "Open". Now you should see an address in the
dialog box, for example "C:\MyDocuments\mypage.htm".
Click OK, and the browser will display the
page.
Example
Explained
The first tag
in your HTML document is <html>. This tag tells
your browser that this is the start of an HTML document.
The last tag in your document is </html>. This tag
tells your browser that this is the end of the HTML
document.
The text
between the <head> tag and the </head> tag
is header information. Header information is not
displayed in the browser window.
The text
between the <body> tags, is the text that will be
displayed in your browser.
The text
between the <title> tags is the title of your
document. The title is displayed in your browser's
caption.
The text
between the <b> and </b> tags will be
displayed in a bold font
HTML
Tags
- HTML tags
are used to mark-up HTML elements
- HTML tags
are surrounded by the two characters < and
>
- The
surrounding characters are called angle
brackets
- HTML tags
normally come in pairs like <b> and
</b>
- The first
tag in a pair is the start tag, the second tag is the
end tag
- The text
between the start and end tags is the element
content
- HTML tags
are not case sensitive, <b> means the same as
<B>
HTML
Elements
Remember the
HTML example from the previous page:
<html>
<head>
<title>Title of page</title>
</head>
<body>
This is my first homepage. <b>This text is bold</b>
</body>
</html> |
This is an
HTML element:
The HTML
element starts with a start tag: <b>
The content of the
HTML element is: This text is bold
The HTML element
ends with an end tag: </b>
The purpose
of the <b> tag is to define an HTML element that
should be displayed as bold.
This is also
an HTML element:
<body>
This is my first homepage. <b>This text is bold</b>
</body> |
This HTML
element starts with the start tag <body>, and ends
with the end tag </body>.
The purpose
of the <body> tag is to define the HTML element
that contains the body of the HTML document.
Why do We
Use Lowercase Tags?
We have just
said that HTML tags are not case sensitive: <B>
means the same as <b>. When you surf the Web, you
will notice that most tutorials use uppercase HTML tags
in their examples. We always use lowercase tags.
Why?
If you want
to prepare yourself for the next generations of HTML you
should start using lowercase tags. The World Wide Web
Consortium (W3C) recommends lowercase tags in their HTML
4 recommendation, and XHTML (the next generation HTML)
demands lowercase tags.
Tag
Attributes
Tags can have attributes. Attributes
can provide additional information about the HTML
elements on your page.
This tag
defines the body element of your HTML page:
<body>. With an added bgcolor attribute, you can
tell the browser that the background color of your page
should be red, like this: <body
bgcolor="red">.
This tag
defines an HTML table: <table>. With an added
border attribute, you can tell the browser that the
table should have no borders: <table
border="0">
Attributes
always come in name/value pairs like this:
name="value".
Attributes
are always added to the start tag of an HTML
element.
Quote
Styles, "red" or 'red'?
Attribute
values should always be enclosed in quotes. Double style
quotes are the most common, but single style quotes are
also allowed.
In some rare
situations, like when the attribute value itself
contains quotes, it is necessary to use single
quotes:
name='John
"ShotGun" Nelson'
Basic HTML
Tags
Headings
Headings are
defined with the <h1> to <h6> tags.
<h1> defines the largest heading. <h6>
defines the smallest heading.
<h1>This is a heading</h1>
<h2>This is a heading</h2>
<h3>This is a heading</h3>
<h4>This is a heading</h4>
<h5>This is a heading</h5>
<h6>This is a heading</h6> |
HTML
automatically adds an extra blank line before and after
a heading.
Paragraphs
Paragraphs
are defined with the <p> tag.
<p>This is a paragraph</p>
<p>This is another paragraph</p> |
HTML
automatically adds an extra blank line before and after
a paragraph.
Line
Breaks
The
<br> tag is used when you want to end a line, but
don't want to start a new paragraph. The <br> tag
forces a line break wherever you place it.
<p>This <br> is a para<br>graph with line breaks</p> |
The
<br> tag is an empty tag. It has no closing
tag.
Comments
in HTML
The comment
tag is used to insert a comment in the HTML source code.
A comment will be ignored by the browser. You can use
comments to explain your code, which can help you when
you edit the source code at a later date.
Note that you
need an exclamation point after the opening bracket, but
not before the closing bracket.
Basic
Notes - Useful Tips
When you
write HTML text, you can never be sure how the text is
displayed in another browser. Some people have large
computer displays, some have small. The text will be
reformatted every time the user resizes his window.
Never try to format the text in your editor by adding
empty lines and spaces to the text.
HTML will
truncate the spaces in your text. Any number of spaces
count as one. Some extra information: In HTML a new line
counts as one space.
Using empty
paragraphs <p> to insert blank lines is a bad
habit. Use the <br> tag instead. (But don't use
the <br> tag to create lists. Wait until you have
learned about HTML lists.)
You might
have noticed that paragraphs can be written without the
closing tag </p>. Don't rely on it. The next
version of HTML will not allow you to skip ANY closing
tags.
HTML
automatically adds an extra blank line before and after
some elements, like before and after a paragraph, and
before and after a heading.
We use a
horizontal rule (the <hr> tag), to separate the
sections in our tutorials.
Basic HTML
Tags:
NN: Netscape,
IE: Internet Explorer
| Start Tag |
NN |
IE |
Purpose |
| <html> |
3.0 |
3.0 |
Defines a html
document |
| <body> |
3.0 |
3.0 |
Defines the document's
body |
| <h1>-<h6> |
3.0 |
3.0 |
Defines heading 1 to heading
6 |
| <p> |
3.0 |
3.0 |
Defines a
paragraph |
| <br> |
3.0 |
3.0 |
Inserts a single line
break |
| <hr> |
3.0 |
3.0 |
Defines a horizontal
rule |
| <!--> |
3.0 |
3.0 |
Defines a comment in the HTML
source code |
|
