HyperText Markup Language (HTML) is the most used of all the markup
languages. It is used to define documents used on the world wide web
The term 'HyperText' means that it is possible to jump to another document
using embedded links - usually by clicking on them with the mouse.
'Markup' means that the documents are made up of tags, which define items on the
page such as images and tables as well as the way text is displayed. The
tags are invisible to the user - only the effects of the tags are seen.
Put together, web pages can be created with many multimedia elements (if
supported by the user's browser), with links to any other page available on the
Tags are probably the most important part of HTML. They are used to
define items on the page as well as specify how text appears. There is a
tag for almost every purpose e.g. the IMG tag defines an
image, the A tag defines a hyperlink, the TEXTAREA
tag defines a multiline textbox for use as part of a form etc. There are
about 94 tags - however not all browsers will have support for every tag.
Tags in HTML documents are surrounded with the '<' and '>' characters
to allow the browser to recognise them as tags. Many tags have to be
closed i.e. where their effect is ended. Tags are closed in the same way
in which they are opened except that you must use the '/' character before the
tag name. An example would be the B tag, which causes
text to render as bold:
<b>This text will render in bold</b>
This text will render in bold
Any text before the opening <b> tag and after the closing </b>
tag will not render in bold.
When using a tag that does not have a closing tag, a space and a '/' character
should be used before the '>' character e.g. <br />. However this
is not absolutely necessary.
An important feature of HTML is that different tags can be used within each
other (called nesting) to combine the effect of two or more tags. E.g.:
<b>This text will render in bold <i>and this text will render in
bold and italic</i></b>
This text will render in bold and this text will render in bold and
As you can see with the above example, the tag that is opened first, in this
case B, must be closed last. Nesting tags is also used
where tags are related i.e. when defining cells and rows in a table.
Certain tags must be used when writing an HTML document. The HTML
tag must be defined first, which defines the page as being an HTML
document. Within this tag, the HEAD tag is defined
to define information about the page such as the author and title etc. All
the visible parts of the document are contained within the BODY
tag (after the HEAD tag has been closed).
Therefore the basic layout of an HTML document looks like this:
See the Tag Reference
to find out what tag to use to generate a specific effect.
Many tags have attributes, which can be changed to alter the
effect of the tag. For example the WIDTH attribute of the IMG
tag specifies how wide the image should be. See the next section for how
to use attributes.