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<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1">
<TITLE>Acorn Internet: World Wide Web pages</TITLE>
<META NAME="GENERATOR" CONTENT="Internet Assistant for Microsoft Word 2.04z">
</HEAD>
<BODY>
<P>
<TABLE WIDTH=100%>
<TR><TD>
<BODY bgcolor="ffffff"><A NAME="_Toc401045867"><FONT SIZE=6>11 <A NAME="World">World</A> Wide Web pages</FONT></A>
</TD><TD ALIGN="RIGHT"><A HREF="jashk"><IMG SRC="MiscImages/PREV" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="../Cover"><IMG SRC="MiscImages/START" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="prelms"><IMG SRC="MiscImages/CONTS" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="appxa"><IMG SRC="MiscImages/NEXT" WIDTH="36" HEIGHT="36" BORDER="0"></A>
</TD></TR>
</TABLE>
<HR>
<H2><A NAME="What">What are Web pages?</A></H2>
<P>
<FONT SIZE=3>Web pages are documents created by authors using
a combination of plain text and a markup language called HTML
(HyperText Markup Language). HTML uses short codes (also known
as tags) to define the structure of a document (headings, paragraphs,
lists, and so on) as well as graphical elements and links within
the document. An HTML document that is available on the Web is
usually known as a Web page.</FONT>
<P>
<FONT SIZE=3>Clicking on a link in a Web page brings another page
located on a local or remote server to your computer, irrespective
of the server's geographic location. Pages can contain text, images,
sounds, movies, or a combination of all these.</FONT>
<H2><A NAME="Creating">Creating Web pages</A></H2>
<P>
<FONT SIZE=3>HTML documents are in plain ASCII text format and
you can create them using any text editor, inserting the markup
codes manually into the text. Alternatively, you can use an HTML
editor such as HTMLEdit, which can make inserting the correct
codes easier.</FONT>
<H3>HTML tags</H3>
<P>
<FONT SIZE=3>HTML uses embedded codes (tags) to designate graphical
elements and links. You can create these codes simply from your
keyboard using angled brackets and the slash character. For example,
the tag <B><B></B> presents text in bold letters. An HTML
source file containing the expression <B><B>This text appears
in bold.</B></B> is displayed on screen in bold. Notice
that the tag <B></B></B> is needed to indicate the end of
the bold expression.</FONT>
<P>
<FONT SIZE=3>HTML consists of many tags like this which are used
both for indicating the structure of a document and defining hyperlinks
embedded in the document.</FONT>
<UL>
<LI><FONT SIZE=3>Document structure tags can be used to mark the
title and body of a document, different levels of heading, bulleted
lists, paragraph breaks and typographical variations (bold, Italic).
</FONT>
<LI><FONT SIZE=3>Link tags define links to other documents or
images.</FONT>
</UL>
<H3>Creating links</H3>
<P>
<FONT SIZE=3>Here's an example which creates a link for users
to click on:</FONT>
<P>
<TT><FONT SIZE=3 FACE="Courier"><A HREF="http://www.acorn.com/acorn/Home">Acorn
Home Page</A></FONT></TT>
<P>
<FONT SIZE=3>This link is made up of three main elements:</FONT>
<UL>
<LI><FONT SIZE=3>The opening and closing tags. The tag code </FONT><TT>A
HREF=</FONT></TT><FONT SIZE=3> signals the start of a link, while
the closing tag </FONT><TT></A></FONT></TT><FONT SIZE=3>
signals the end of the link.</FONT>
<LI><FONT SIZE=3>The part of the tag between quotation marks is
the URL of the page brought by clicking on the link. (<A HREF="#URLs" >See Identifying resources - URLs</A>
for more about URLs.)</FONT>
<LI><FONT SIZE=3>The text following the URL contains the text
which appears highlighted on the screen (in this example, "Acorn
Home Page"). </FONT>
</UL>
<H3>Looking at HTML source</H3>
<P>
<FONT SIZE=3>You can look at any page's HTML source by choosing
the <B>Display page source</B> option from the button bar. You can then examine all the text
and tags used to define the content and style of the page.</FONT>
<H2><A NAME="Identifying">Identifying</A> resources - <A NAME="URLs">URLs</A>
</H2>
<P>
<FONT SIZE=3>Every single page on the World Wide Web has an identifier,
called a URL, short for Uniform Resource Locator. The URL both
locates and uniquely identifies resources on the Web. Using the
URL, browsers like Acorn Internet software can find a particular
page or file among all the computers connected to the Internet.
</FONT>
<P>
<FONT SIZE=3>Here's a sample URL: </FONT>
<P>
<TT>http://www.acorn.com/acorn/Home</FONT></TT>
<P>
<FONT SIZE=3>The URL is made up of three separate components:
</FONT>
<UL>
<LI><FONT SIZE=3>The <B>protocol</B> - the method used for transferring
files across a network.</FONT>
<LI><FONT SIZE=3>The <B>domain name</B> - the name and location
of the server computer.</FONT>
<LI><FONT SIZE=3>The <B>pathname</B> of the resource - the filename
and the name of the directory where the resource is stored.</FONT>
</UL>
<H3>Protocol</H3>
<P>
<FONT SIZE=3>The first component in a URL, the protocol, is followed
by a colon, for example, </FONT><TT>http:</FONT></TT><FONT SIZE=3>.
It identifies how computers will talk to each other across a network.
</FONT>
<P>
<FONT SIZE=3>Web pages use HTTP (short for HyperText Transfer
Protocol). Other common protocols you might come across in URLs
include:</FONT>
<H4>file:</H4>
<P>
<FONT SIZE=3>When you see </FONT><TT>file:</FONT></TT><FONT SIZE=3>
at the front of a URL, it means that the resource is stored on
your local system</FONT>
<H4>Mail to:</H4>
<P>
<FONT SIZE=3>Starts the mail application to send a mail message
to the required destination.</FONT>
<H4>ftp:</H4>
<P>
<FONT SIZE=3>Short for File Transfer Protocol, this is an alternative
protocol for moving files from one computer to another. For example,
the Acorn FAQ document is available from the following ftp site:</FONT>
<P>
<TT><FONT SIZE=3 FACE="Courier">ftp://rtfm.mit.edu/pub/usenet/news.answers/acorn/faq</FONT></TT>
<H4>gopher:</H4>
<P>
<FONT SIZE=3>Another alternative transfer protocol that allows
you to browse for resources via simple text menus. For example,
the Queensland University of Technology Gopher has this URL:</FONT>
<P>
<TT>gopher://gopher2.qut.edu.au/</FONT></TT>
<H4>telnet:</H4>
<P>
<FONT SIZE=3>A protocol that allows you to log in to other computers
on the Internet. For example, you can log into the Cambridge University
Library computer and search their catalogue by author, title or
subject:</FONT>
<P>
<TT>telnet://ul.cam.ac.uk/</FONT></TT>
<H4>news:</H4>
<P>
<FONT SIZE=3>The protocol used by Usenet news groups. For example,
this is the URL for the comp.sys.acorn newsgroup, a newsgroup
for announcements about Acorn and Acorn products:</FONT>
<P>
<TT>news:comp.sys.acorn.announce</FONT></TT>
<H3>Domain name</H3>
<P>
<FONT SIZE=3>The second component in the URL, the domain name,
is preceded by two slashes, for example </FONT><TT>//www.acorn.com</FONT></TT><FONT SIZE=3>.
This part identifies the computer that stores the information
you're seeking. </FONT>
<P>
<FONT SIZE=3>Each server on the Internet has a unique address
to distinguish it from all the other servers on the Internet -
the domain name. The domain name is broken into several subparts
(a host name and zero or more subdomains), with each part separated
by a dot (the full stop symbol is pronounced "dot").
The subparts are organised in a hierarchical sequence from the
left (the most specific part of the address) to the right (the
most general part of the address). You can often tell what kind
of organisation is operating the server and where the server is
located from its address or domain name.</FONT>
<P>
<FONT SIZE=3>A domain name starts with the name of the server
computer, and may also include the name and type of the organisation
providing the server, and the country where the server is located.
For example:</FONT>
<P>
<TT>www.acorn.com</FONT></TT>
<P>
<FONT SIZE=3>This is the domain name address for the Acorn Computers
Web server, where;</FONT>
<P>
<TT>www</FONT></TT><FONT SIZE=3> = the name
of the server computer</FONT>
<P>
<TT>acorn</FONT></TT><FONT SIZE=3> = the
name of the company</FONT>
<P>
<FONT SIZE=3>com = the type of organisation (commercial)</FONT>
<P>
<TT>www.canterbury.ac.nz</FONT></TT>
<P>
<FONT SIZE=3>This is the domain named address for the University
of Canterbury Web server in New Zealand, where</FONT>
<P>
<TT>www</FONT></TT><FONT SIZE=3> = the name
of the server computer</FONT>
<P>
<TT>canterbury</FONT></TT><FONT SIZE=3> =
the name of the University </FONT>
<P>
<TT>ac</FONT></TT><FONT SIZE=3> = the type
of organisation (academic)</FONT>
<P>
<TT>nz</FONT></TT><FONT SIZE=3> = New Zealand</FONT>
<P>
<TT>george.lbl.gov</FONT></TT>
<P>
<FONT SIZE=3>This is the domain name for the Lawrence Berkeley
National Laboratory Web server in the United States:</FONT>
<P>
<TT>george</FONT></TT><FONT SIZE=3> = the
name of the server computer</FONT>
<P>
<TT>lbl</FONT></TT><FONT SIZE=3> = the name
of the organisation</FONT>
<P>
<TT>gov</FONT></TT><FONT SIZE=3> = the type
of organisation (US Government)</FONT>
<P>
<FONT SIZE=3>Here are some other common suffixes and their regional
and organisational affiliations:</FONT>
<UL>
<LI><FONT SIZE=3>.co (commercial)</FONT>
<LI><FONT SIZE=3>.ac (educational)</FONT>
<LI><FONT SIZE=3>.uk (United Kingdom)</FONT>
<LI><FONT SIZE=3>.nl (The Netherlands)</FONT>
<LI><FONT SIZE=3>.au (Australia)</FONT>
<LI><FONT SIZE=3>.gov (US government)</FONT>
<LI><FONT SIZE=3>.com (US commercial)</FONT>
<LI><FONT SIZE=3>.edu (US educational)</FONT>
</UL>
<H3>Pathname</H3>
<P>
<FONT SIZE=3>The last component of the URL is the remote pathname
which identifies the location of the page on the server. Each
segment of the pathname is preceded by a single forward slash.</FONT>
<P>
<FONT SIZE=3>A pathname might identify a page by specifying the
name of the file comprising the page (such as</FONT><TT>
/welcome</FONT></TT><FONT SIZE=3>) as well as the name of
one or more subdirectories that store the file (for example, </FONT><TT>/acorn</FONT></TT><FONT SIZE=3>
or </FONT><TT>/acorn/library/ref</FONT></TT><FONT SIZE=3>).</FONT>
<H2><A NAME="Serving">Serving</A> pages</H2>
<P>
<FONT SIZE=3>You can use the Acorn Internet proxy/cache server
to serve your own pages to other Web users on a local network.</FONT>
<OL>
<LI><FONT SIZE=3>First set up a local page cache as described
in <A HREF="confbr#Browser" >Browser configuration</A>.</FONT>
<LI><FONT SIZE=3>Create a Web page in HTML format. Double-click
on !WebCache, which you will find in the same directory as !Browse,
and a directory display will appear. Save the HTML file into the
directory with a suitable name.</FONT>
<LI><FONT SIZE=3>Make sure that you set the file's expiry time
to a suitable length (see <A HREF="confbr#cache" >Setting the local cache size and expiry times</A>).</FONT>
<LI><FONT SIZE=3>Restart WebServe.</FONT>
</OL>
<P>
<FONT SIZE=3>Local Web users will be able to request the page
by entering its address in the format:</FONT>
<P>
<TT>http://node_name/page_pathname </FONT></TT>
<P>
<FONT SIZE=3>where </FONT><TT>node_name</FONT></TT><FONT SIZE=3>
is the IP name of the server. (Note that URLs are case-sensitive.)</FONT>
<P>
<FONT SIZE=3>In some limited circumstances, you can also serve
pages to remote users, if</FONT>
<OL>
<LI><FONT SIZE=3>you have a permanently open phone line, and</FONT>
<LI><FONT SIZE=3>your service provider allocates you a fixed IP
address (and not a dynamic one).</FONT>
</OL>
<P>
<FONT SIZE=3>In such a case, remote users could access your locally-cached
pages by requesting:</FONT>
<P>
<TT><FONT SIZE=3 FACE="Courier">http://node_name.service_provider/page_pathname
</FONT></TT>
<P>
<FONT SIZE=3>where <TT>node_name</TT> is your Internet name, by which you are known by your service provider (e.g. <TT>bashstrt</TT> in <TT>bashstrt.demon.uk</TT>).
</FONT>
<P>
<A HREF="jashk"><IMG SRC="MiscImages/PREV" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="../Cover"><IMG SRC="MiscImages/START" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="prelms"><IMG SRC="MiscImages/CONTS" WIDTH="36" HEIGHT="36" BORDER="0"></A><A HREF="appxa"><IMG SRC="MiscImages/NEXT" WIDTH="36" HEIGHT="36" BORDER="0"></A>
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