The first bit of this part is not really advanced, but it deals with some things that didn't fit anywhere else: block text, mathematics and tables. The other two sections cover the inclusion of external files and images, and the new form-fill feature of HTML+ which is already included in some clients.
Block text is text that is set off from the surrounding paragraph by being indented or separated by some space. There are two tags to do this:
</address>which is for surrounding people's addresses. In some browsers it may also cause a font change. It does not honor linebreaks, so if you need to split the address up into separate lines, use the
<br>tag: Peter Flynn
</blockquote>is for block quotations. Browsers may indent this or otherwise set it off from the surrounding text. It does not honor linebreaks, so if you need to split the address up into separate lines, use the
Zerbrochen ist das Steuer und es krachtThis tag will be renamed to
Das Schiff an allen Seiten. Berstend reißt
Der Boden unter meinen Füssen auf!
Ich fasse Dich mit beiden Armen an!
So klammert sich der Schiffer endlich noch
Am Felsen fest, an dem er scheitern sollte!
- Johann Wolfgang von Goethe, `Torquato Tasso'
HTML as it currently stands does not define any tags for math or tabulations, so you can't type them in directly like you can in TeX or LaTeX. HTML+ may contain math and tables definitions, but in any event, the jury is still out on math in SGML.
However, there are some simple fixes for this:
There are two mechanisms for including other files at a given point
in your document.
<img> is for including graphic images
<inc> is for text files.
<inc> is not in the original HTML but is a new
Graphics can be included at any point with the
src="...">: tag (defined empty, so there's no end-tag
involved). You supply the URL (in
quotes) of the graphics file, which must be in one of the following
Users with text-only clients will obviously not get the graphics,
but the client may display a marker like [IMAGE] where the
graphic would normally come. To make this more meaningful, another new
optional attribute to the
<img...> tag has been
alt="..." which lets you supply alternate identifying
replacement text in quotes which non-graphical browsers can display in
place of just saying [IMAGE]. Setting it to null (alt="")
is a way of preventing non-graphical browsers from displaying anything at
all in place of the image.
Take care in including images: many users who are on slow lines or congested networks do not appreciate the wait while their client downloads megabytes of pretty but inessential pictures.
If you include the
ISMAP attribute in a
src="..."> reference, it is possible to arrange for some
browsers to transmit mouse coordinates to a mapping server
(mapd) which will take appropriate action depending on
whereabouts within the graphic the mouse was located when it was
Still pictures are not the only things you can include in your
document. If your readers have MPEG viewers or audio support, you can
<img src="..."> mechanism to refer to movie
clips and sound files, which brings W3 into the multimedia field.
The warning above about transmission time applies doubled here: movies over the network take a lot of bandwidth.
Some systems (notably Mosaic and the NCSA server) allow the in-line inclusion of external files. This is not a part of the original HTML but will likely be included in HTML+.
To include such a file, use the
<inc srv "...">
tag (defined empty, so there's no end-tag) giving the name of the file
in quotes. The directory and path should be given as from the
server-root of the server being referenced. The file will be
interpreted as HTML and formatted accordingly: to display it as plain
text, enclose the
<srv...> tag in one of the fixed-width
display elements. Here's a local file I included this way:
The form-fill feature is a proposed enhancement in HTML+ which Mosaic, Lynx and some other browsers have started to support.
A form is made up of text interspersed with a series of input areas which the user can fill in, and finally send the completed form to a destination you (the author) specify. In most cases this destination is a HTTP server, which will run a script or program to parse (check) the input data and then file or process it or send it to a specified email address. Details of how to specify processing are complex and beyond the scope of this document: you should read (for example) the NCSA's documentation.
Here is a brief overview of the structure of a form and how to specify the input areas (fields). If you want to use forms, you need to have access to a server where you can place the script or program which you want to process the data.
A form must be entirely defined within
</form> tags. The
attributes for the start-tag are:
There's more information on the NCSA's own server.
That's it, there is no more to HTML (yet...wait for HTML+)
Please let me know if you find errors or other deficiencies in this document:Peter Flynn