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- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
- <HTML><HEAD>
- <TITLE>A Beginner's Guide to HTML</TITLE></HEAD>
- <BODY>
-
- <H1>A Beginner's Guide to HTML</H1>
-
- This is a primer for producing documents
- in HTML, the markup language used by the World Wide Web.
-
- <UL>
- <LI> <A NAME=14 HREF="#Acronyms">Acronym expansion
- - the World Wide Web alphabet soup</A>
- <LI> <A NAME=15 HREF="#MinimalHTML">The minimal HTML document</A>
- <UL>
- <LI><A HREF="#Titles">Titles</A>
- <LI><A HREF="#Headings">Headings</A>
- <LI> <A HREF="#Paragraphs">Paragraphs</A>
- </UL>
- <LI> <A NAME=18 HREF="#Links">Linking to other documents</A>
- <UL>
- <LI> <A NAME=19 HREF="#URL">Uniform Resource Locator (URL)</A>
- <LI> <A NAME=20 HREF="#NamedAnchorOther">Anchors to specific sections
- in other documents</A>
- <LI> <A NAME=21 HREF="#NamedAnchorSame">Anchors to specific sections
- in the same document</A>
- </UL>
-
- <LI> <A NAME=22 HREF="#MoreTags">Additional markup tags</A>
- <UL>
- <LI> <A NAME=23 HREF="#Lists">Lists</A>
- <UL>
- <LI><A NAME=24 HREF="#UnnumberedLists">Unnumbered lists</A>
- <LI><A NAME=25 HREF="#NumberedLists">Numbered lists</A>
- <LI> <A NAME=26 HREF="#DescriptiveLists">Descriptive lists</A>
- <LI> <A NAME=27 HREF="#NestedLists">Nested Lists</A>
- </UL>
-
- <LI> <A NAME=28 HREF="#Preformatted">Preformatted text</A>
- <LI> <A NAME=29 HREF="#Blockquote">Extended quotes</A>
- <LI> <A NAME=30 HREF="#CharFormat">Character formatting</A>
- <LI> <A NAME=31 HREF="#SpecialChar">Special characters</A>
- </UL>
-
- <LI> <A NAME=32 HREF="#InlineImage">Inline images</A>
- <LI> <A NAME=33 HREF="#ExternalImage">External images</A>
- <LI> <A NAME=34 HREF="#Troubleshooting">Troubleshooting</A>
- <LI> <A NAME=35 HREF="#ExtendedExample">A longer example</A>
- <LI> <A NAME=36 HREF="#MoreInfo">For more information</A>
- </UL>
-
- <A NAME="Introduction">
- <H2>Introduction</H2>
- </A>
-
- <A NAME="Acronyms">
- <H3>Acronym expansion</H3>
- </A>
-
- <DL>
- <DT> <i>WWW</I>
- <DD> World Wide Web
- <DT> <i>SGML</I>
- <DD> Standard Generalized Markup Language - This is perhaps best be
- thought of as a programming language for style sheets.
- <DT> <i>DTD</I>
- <DD> Document Type Definition - This is a specific implementation
- of document description using SGML.
- One way to think about this is: Fortran is to a computer program as
- SGML is to a DTD.
- <DT> <i>HTML</I>
- <DD> HyperText Markup Language - HTML is a SGML DTD. In practical terms,
- HTML is a collection of styles used to define the various components
- of a World Wide Web document.
- <DT>
- <DD>
- </DL>
-
- <A NAME="NotCovered">
- <H3>What this primer doesn't cover</H3>
- </A>
-
- This primer assumes that you have:
- <UL>
- <LI> at least a passing knowledge of how to use NCSA
- Mosaic or other WWW browser
- <LI> a general understanding of how World Wide Web servers
- and client browsers work and
- <LI> access to a World Wide Web server for
- which you would now like to produce HTML documents
- </UL>
-
- <A NAME="CreatingHTML">
- <H3>Creating HTML documents</H3>
- </A>
-
- HTML documents are in plain text format and can be created using any
- text editor (e.g., Emacs or vi on Unix machines).
- A couple of WWW browsers (tkWWW for X Window System machines and
- CERN's WWW browser for the NeXT) do include rudimentary HTML editors
- in a WYSIWYG environment, and you may want to try one of them first
- before delving into the details of HTML. <P>
-
- <blockquote>
- <i>
- You can preview documents in progress with NCSA Mosaic (and some other
- WWW browers).
- Open the document using the Open Local option under the <b>File</b> menu.
- Use the Filters,
- Directories, and Files fields to locate the document or
- enter the path and name of the document in the
- Name of Local Document to Open field. Press OK.
- </p>
-
- If you see
- edits you want to make, enter them in the source file. Save the changes.
- Return to NCSA Mosaic and press the <b>Reload</b> button on the
- bottom menu. The edits are reflected in the on-screen display.<P>
- </i>
- </blockquote>
-
- <A NAME="MinimalHTML">
- <H2>The minimal HTML document</H2>
- </A>
-
- Here is a barebones example of HTML: <P>
- ____________________________________________________________________
- <PRE>
- <TITLE>The simplest HTML example</TITLE>
-
- <H1>This is a level one heading</H1>
-
- Welcome to the world of HTML.
- This is one paragraph.<P>
-
- And this is a second.<P>
- </PRE>
- ____________________________________________________________________
- <p>
- <A NAME=10 HREF="/General/Internet/WWW/MinimalHTML.html">Click here</A> to see the formatted
- version of the example.
- <p>
-
- HTML uses <dfn>tags</dfn> to tell the World Web viewer how to display
- the text. The above example uses
-
- <UL>
- <LI> the <code><TITLE></code> tag (which
- has a correspondinging <code></TITLE></code> tag), which specifies
- the title of the document,
- <LI>the <code><H1></code> header tag
- (with corresponding <code></H1></code>), and
- <LI>the <code><P></code> end-of-paragraph tag.
- </UL>
-
- HTML tags consist of a left angular bracket (<code><</code>), known
- as a ``less than'' symbol to mathematicians, followed by some text
- (called the <dfn>directive</dfn>) and closed
- by a right angular bracket (<code>></code>).
- Tags are usually paired, e.g. <code><H1></code> and <code></H1></code>.
-
- The ending tag looks just like the starting tag except
- a slash (/) precedes the text within the brackets.
- In the example, <code><H1></code> tells the viewer to
- start formatting a top level heading;
- <code></H1></code> tells the viewer that the heading is complete.
- <P>
-
- The primary exception to the pairing rule is the <code><P></code>
- end-of-paragraph tag. There is no such thing as <code></P></code>.<P>
-
- <strong>Note:</strong> HTML is <EM>not</EM> case senstive.
- <code><title></code> is completely equivalent
- to <code><TITLE></code> or <code><TiTlE></code>. <P>
-
- Not all tags are supported by all World Wide Web browsers.
- If a browser does not support a tag, it should just ignore it, though. <P>
-
- <A NAME="Titles">
- <H3>Titles</H3>
- </A>
- Every HTML document should have a title. A title is generally
- displayed separately from
- the document and is used primarily for document identification in other
- contexts (e.g., a WAIS search). Choose about half a dozen
- words that describe the document's purpose.
-
- <blockquote>
- <i>
- In NCSA Mosaic, the Document Title field is at the top of the screen
- just below the pulldown menus. <P>
- </i>
- </blockquote>
-
- The directive for the title tag is <code><title></code>.
- The title generally goes on the first line of the document. <P>
-
- <A NAME="Headings">
- <H3>Headings</H3>
- </A>
- HTML has six
- levels of headings (numbered 1 through 6), with 1 being the most prominent.
- Headings are displayed in larger and/or bolder fonts than the normal
- body text. The first heading in each document should be tagged
- <code><H1></code>.
-
- The syntax of the heading tag is:
- <PRE>
- <H<var>y</var>><var>Text of heading</var></H<var>y</var>>
- </PRE>
- where <var>y</var> is a number between 1 and 6 specifying the level
- of the heading. <P>
-
- For example, the coding for the ``Headings'' section heading above is
- <PRE>
- <H3>Headings</H3>
- </PRE>
-
- <strong>Title versus first heading</strong>:
- In many documents (including this one), the first heading is identical
- to the title. For multi-part documents, the text of the first heading
- should be suitable for a reader who is already browsing
- related information (e.g., a chapter title), while the title
- tag should identify the node in a wider context (e.g., include
- both the book title and the chapter title). <P>
-
- <A NAME="Paragraphs">
- <H3>Paragraphs</H3>
- </A>
-
- Unlike documents in most word processors,
- carriage returns and white space in HTML files aren't significant.
- Word wrapping can occur at any point in your source file, and multiple
- spaces are collapsed into a single space (except in
- the <TITLE> field). Notice that in the barebones example,
- the first paragraph is coded as <P>
- <PRE>
- Welcome to HTML.
- This is the first paragraph. <P>
- </PRE>
- In the source file, there is a line break between the sentences.
- A Web browser ignores this line break and starts
- a new paragraph only when it reaches a <code><P></code> tag. <P>
-
- <strong>Important:</strong>
- You must end each paragraph with <code><P></code>. The viewer
- ignores any indentations or blank lines in the source text. Without
- the <code><P></code> tags, the document becomes one large paragraph. HTML
- relies almost entirely on the tags for formatting instructions. (The
- exception is text tagged as ``preformatted,'' explained
- <A NAME=12 HREF="#Preformatted">below</A>.) For instance, the following
- would produce identical output as the first barebones HTML example: <P>
- ________________________________________________________________________
- <PRE>
- <TITLE>The simplest HTML example</TITLE><H1>This is a level
- one heading</H1>Welcome to the world of HTML. This is one
- paragraph.<P>And this is a second.<P>
- </PRE>
- ________________________________________________________________________
- <P>
-
- However, to preserve readability in HTML files, headings should be
- on separate lines, and paragraphs should be separated by blank lines. <P>
-
- <A NAME="Links">
- <H2>Linking to other documents</H2>
- </A>
-
- The chief power of HTML comes from its ability to <dfn>link</dfn> regions
- of text (and also images) to another document (or an image).
- These regions are typically
- highlighted by the browser to indicate that they are hypertext links.
-
- <blockquote>
- <i>
- In NCSA Mosaic, hypertext links are in color and underlined by default.
- It is possible to modify this in the Options menu as well as in your
- .Xdefaults file.
- </i>
- </blockquote>
-
- HTML's single hypertext-related directive is <code>A</code>,
- which stands for anchor. To include anchors in your document: <P>
-
- <OL>
- <LI> Start by opening the anchor with the leading angle bracket
- and the anchor directive followed by a space: <code><a</code>
- <LI> Specify the document that's being pointed to by giving the
- parameter
- <code> href="filename.html" </code> followed by a
- closing angle bracket: <code>></code>
- <LI> Enter the text that will serve as the hypertext
- link in the current document
- (i.e., the text that will be in a
- different color and/or underlined)
- <LI> Enter the ending anchor tag: <code></A></code>
- </OL>
-
- Below is an sample hypertext reference: <P>
-
- <PRE>
- <a href="MaineStats.html">Maine</a>
- </PRE>
-
- This entry makes ``Maine'' the hyperlink to the document
- <samp>MaineStats.html</samp>. <P>
-
- <A NAME="URL">
- <H3>Uniform Resource Locator</h3>
- </A>
-
- A Uniform Resource Locator (URL) refers to the format used by WWW
- documents to locate other files. A URL gives the type of resource being
- accessed (e.g., gopher, WAIS) and the path of the file. The format used is:<p>
-
- <pre>
- <var>scheme</var>://<var>host.domain</var>[:<var>port</var>]/<var>path</var>/<var>filename</var>
- </pre>
-
- where <dfn>scheme</dfn> is one of:
- <DL>
- <DT> <code>file</code>
- <DD> a file on your local system, or a file on an anonymous ftp server
- <DT> <code>http</code>
- <DD> a file on a World Wide Web server
- <DT> <code>gopher</code>
- <DD> a file on a Gopher server
- <DT> <code>WAIS</code>
- <DD> a file on a WAIS server
- </DL>
- The scheme can also be <code>news</code> or <code>telnet</code>, but these
- are used much less often than the above.
-
- The port number can generally be omitted from the URL. <P>
-
- For example if you wanted to insert a link to this primer, you would insert
- <PRE>
- <A HREF="http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html">
- NCSA's HTML Primer</A>
- </PRE>
- into your document. This would make the text ``NCSA's HTML Primer''
- a hyperlink leading to this document. <P>
-
- Refer to the
- <A HREF="http://info.cern.ch/hypertext/WWW/Addressing/Addressing.html">
- Addressing</a> document prepared by CERN for additional
- information about URLs.
- <cite>A Beginner's
- <A HREF="http://www.ncsa.uiuc.edu/demoweb/url-primer.html">Guide</a>
- to URLs</cite> is located
- on the NCSA Mosaic Help menu. <P>
- <A NAME="NamedAnchorOther">
- <h3> Anchors to Specific Sections in Other Documents</h3>
- </A>
- Anchors can also be used to move to a particular section in
- a document.
-
- Suppose you wish to set a link from document A and a specific
- section in document B. First you need to set up what is called
- a <dfn>named anchor</dfn> in document B. For example, to add an
- anchor named ``Jabberwocky" to document B, you would insert
-
- <PRE>
- Here's <A NAME="Jabberwocky">some text</a>.
- </PRE>
-
- Now when you create the link in document A, you include not
- only the filename, but also the named anchor, separated by a hash
- mark(``#''):
-
- <PRE>
- This is my <A HREF="documentB.html#Jabberwocky">link</a>.
- </PRE>
-
- Now clicking on the word ``link'' in document A
- would send the reader directly to the words ``some text'' in document B.
-
- <A NAME="NamedAnchorSame">
- <h3> Anchors to Specific Sections within the Current Document</h3>
- </A>
-
- The technique is exactly the same except the file name is now
- omitted. <P>
-
- <strong>Note:</strong> The NCSA Mosaic <b>Back</b> button does not work
- for an anchor within
- a document because the <b>Back</b> button is designed to move
- to a previous document. Move back manually within the document using the
- scroll bar. (The <b>Back</b> button will return to the start
- of a hyperlink effective with Version 2.0 of NCSA Mosaic.)<p>
-
- <A NAME="MoreTags">
- <H2>Additional markup tags</H2>
- The above is sufficient to produce simple HTML documents. For more
- complex documents, HTML also has tags for several types of lists,
- extended quotes, character formatting and other items, all described
- below.
-
- <A NAME="Lists">
- <H3>Lists</H3>
- </A>
-
- HTML supports unnumbered, numbered, and descriptive lists.
- For list items, no
- paragraph separator is required. The tags for the items in the list
- terminate each list item.
-
- <A NAME="UnnumberedLists">
- <h4> Unnumbered Lists </h4>
- </A>
-
- <oL>
- <LI> Start with an opening list <code><ul></code> tag.
- <LI> Enter the <code><li></code> tag followed by the
- individual item. (Remember that no closing tag is needed.)
- <LI> End with a closing list <code></ul></code> tag.
- </oL>
-
- Below an example two-item list: <P>
-
- <PRE>
- <UL>
- <LI> apples
- <LI> bananas
- </UL>
- </PRE>
-
- The output is:<p>
- <ul>
- <li>apples
- <li>bananas
- </ul>
- <p>
-
- Note that different viewers display an unordered list differently. A viewer
- might use bullets, filled circles, or dashes to show the items. <p>
-
- <A NAME="NumberedLists">
- <h4>Numbered Lists </h4>
- </A>
-
- A numbered list (also called an ordered list, from where the
- abbreviation comes) uses the <code><ol></code>
- directive to start a list
- rather than the <code><ul></code> directive. The items are
- tagged using the same <code><li></code> tag as for a bulleted list.
- For example: <P>
-
- <PRE>
- <OL>
- <LI> oranges
- <LI> peaches
- <LI> grapes
- </OL>
- </PRE>
-
- The list looks like this online:<p>
- <ol>
- <li>oranges
- <li>peaches
- <li>grapes
- </ol>
- <p>
-
- <A NAME="DescriptiveLists">
- <h4>Descriptive Lists </h4>
- </A>
-
- A description list usually consists of alternating a <dfn>description
- title</dfn> (abbreviated as dt) and a <dfn>description description</dfn>
- (abbreviated
- as dd). The description generally starts on a new line, because the viewer
- allows the full line width for the contents of the dt field.<P>
-
- Below is an example description list as included in your source file: <P>
-
- <PRE>
- <DL>
- <DT> National Center for Supercomputing Applications
- <DD> NCSA is located on the campus of the University
- of Illinois at Urbana-Champaign. NCSA is a one of
- four member institutions in the National Metacenter for
- Computational Science and Engineering.
- <DT> Cornell Theory Center
- <DD> CTC is located on the campus of Cornell
- University in Ithaca, New York. CTC is another member
- of the National Metacenter for Computational Science
- and Engineering.
- </DL>
- </PRE>
-
- The output looks like this: <P>
-
- <DL>
- <DT> National Center for Supercomputing Applications
- <DD> NCSA is located on the campus of the University of Illinois
- at Urbana-Champaign. NCSA is a one of four member institutions in the
- National Metacenter for Computational Science and Engineering.
- <DT> Cornell Theory Center
- <DD> CTC is located on the campus of Cornell University in Ithaca,
- New York.
- CTC is another member of the National Metacenter for Computational
- Science and Engineering.
- </DL>
-
- The <code><DT></code> and <code><DD></code>
- entries can contain multiple
- paragraphs (separated by paragraph tags), lists, or other description
- information. <P>
-
- <A NAME="NestedLists">
- <h4> Nested Lists </h4>
- </A>
-
- Lists can be arbitrarily nested. A list item can itself contain
- lists. You can also have a number of paragraphs, each themselves containing
- nested lists, in a single list item, and so on. <p>
-
- Remember that the display of an unordered list varies with the
- viewer. A browser may not provide
- successive levels of indentation or modify the bullets used at each level.
-
- <blockquote>
- <i>
- NCSA
- Mosaic indents the second level in the following list and changes
- the ``bullet'' from a bullet to a small box.<P>
- </i>
- </blockquote>
-
- An example nested list: <P>
-
- <PRE>
- <UL>
- <LI> A few New England states:
- <UL>
- <LI> Vermont
- <LI> New Hampshire
- </UL>
- <li> One Midwestern state:
- <UL>
- <LI> Michigan
- </UL>
- </UL>
- </PRE>
-
- The nested list is displayed as <P>
-
- <UL>
- <LI> A few New England states:
- <UL>
- <LI> Vermont
- <LI> New Hampshire
- </UL>
- <LI>One Midwestern state:
- <UL>
- <LI> Michigan
- </UL>
- </UL>
-
- <A NAME="Preformatted">
- <H3>Preformatted Text</H3>
- </A>
-
- Use the <code>pre</code> tag (which stands for ``preformatted'')
- to include text in a fixed-width font and to cause
- spaces, new lines, and tabs to be significant. This is
- useful for program
- listings. For
- example, the following lines in your source file: <P>
-
- <pre>
- <PRE>
- #!/bin/csh
- cd $SCR
- cfs get mysrc.f:mycfsdir/mysrc.f
- cfs get myinfile:mycfsdir/myinfile
- fc -02 -o mya.out mysrc.f
- mya.out
- cfs save myoutfile:mycfsdir/myoutfile
- rm *
- </PRE>
- </pre>
-
- display as:
-
- <PRE>
- #!/bin/csh
- cd $SCR
- cfs get mysrc.f:mycfsdir/mysrc.f
- cfs get myinfile:mycfsdir/myinfile
- fc -02 -o mya.out mysrc.f
- mya.out
- cfs save myoutfile:mycfsdir/myoutfile
- rm *
- </PRE>
-
- Hypertext references (and other HTML tags)
- can be used within <pre> sections.
-
- <A NAME="Blockquote">
- <H3>Extended quotes</H3>
- </A>
-
- Use the <code><blockquote></code> and <code></blockquote></code>
- tags to include
- quotations in a separate block on the screen. <P>
-
- For example
- <PRE>
- <blockquote>
- Let us not wallow in the valley of despair. I say to you, my
- friends, we have the difficulties of today and tomorrow. <P>
-
- I still have a dream. It is a dream deeply rooted in the
- American dream. <P>
-
- I have a dream that one day this nation will rise up and
- live out the true meaning of its creed. We hold these truths
- to be self-evident that all men are created equal. <P>
- </blockquote>
- </PRE>
-
- The result is
- <blockquote>
- Let us not wallow in the valley of despair. I say to you, my
- friends, we have the difficulties of today and tomorrow.<P>
-
- I still have a dream. It is a dream deeply rooted in the
- American dream.<P>
-
- I have a dream that one day this nation will rise up and
- live out the true meaning of its creed. We hold these
- truths to be self-evident that all men are created equal.<P>
- </blockquote>
-
- <A NAME="Addresses">
- <H3>Addresses</H3>
- </A>
-
- The <code><ADDRESS></code> tag is generally used
- within HTML documents to specify
- the author of a document and provides a means of contacting the author (e.g.,
- an email address). This is usually the last item in a file and generally
- starts on a new, left-justified line. <P>
-
- For example, the last part of the HTML file for this primer is
- <PRE>
- <ADDRESS>
- A Beginner's Guide to HTML / NCSA / pubs@ncsa.uiuc.edu
- </ADDRESS>
- </PRE>
-
- The result is:<p>
- <address>A Beginner's Guide to HTML / NCSA / pubs@ncsa.uiuc.edu</address> <P>
-
- <A NAME="CharFormat">
- <H3>Character formatting</H3>
- </A>
-
- Individual words or sentences can be put in special styles.
- <dfn>Logical</dfn> styles are
- those that are configured by your viewer. For example,
- <code><CITE></code>
- may be defined as italic by your viewer. Each time you enter
- <code><CITE></code>
- tags, the viewer automatically displays the text in italics. <p>
-
- A <dfn>physical</dfn> style
- is one that you determine, and the viewer displays
- what you have coded. For example
- <code><I></code> tells the viewer to
- display your text in italics. <P>
-
- For HTML-coded documents, you should use
- logical styles whenever possible. Future
- implementations of HTML may not implement physical styles at all. <p>
-
- <UL>
- <li>Italic
- <ul>
- <LI> <code><I>text</i></code> puts text in italics
- (<i>HTML Primer</i>)
- <li> <code><em>text</em></code> also italicizes text (only <em>one</em> viewer)
- <li> <code><cite>text</cite></code> is used for citations of names
- of manuals, sections, or books (<cite>HTML Primer</cite>)
- <li> <code><var>text</var></code> indicates a
- variable (<var>filename</var>)
- </ul>
- <li>Bold
- <ul>
- <LI> <code><b>text</b></code> puts text in bold
- (<b>Important</b>)
- <li> <code><strong>text</strong></code> also emphasizes
- text (<strong>Note:</strong>)
- </ul>
- <li>Fixed width font
- <ul>
- <LI> <code><tt>text</tt></code> puts text in a fixed-width
- font (<tt>1 SU = 1 CPU hour</tt>)
- <LI> <code><code>text</code></code> also puts text in
- a fixed-width font (<code>1 SU = 1 CPU hour</code>)
- <li> <code><samp>text</samp></code> formats text for samples
- (<samp>-la</samp>)
- <li> <code><kbd>text</kbd></code> displays the names of
- keys on the keyboard (<kbd>HELP</kbd>)
- </ul>
- <li>Other (the following special tag currently does not display in NCSA Mosaic)
- <ul>
- <li> <code><dfn>text</dfn></code>
- displays a definition in italics
- </ul>
- </UL>
-
- <A NAME="SpecialChar">
- <H3>Special Characters</H3>
- </A>
-
- Three <A NAME=characters>characters</A> out of the entire ASCII (or ISO 8859) character set
- are <i>special</i> and cannot be used ``as-is'' within an HTML document.
- These characters are left angle bracket (<code><</code>), right
- angle bracket (<code>></code>), and ampersand (<code>&</code>). <P>
-
- The angle brackets are used to specify HTML tags (as
- shown above), while the ampersand is used as the escape mechanism
- for these and other characters:
-
- <UL>
- <LI> <code><</code> is the <i>escape sequence</i> for
- <code> <</code>
- <LI> <code>></code> is the escape sequence for
- <code> ></code>
- <LI> <code>&</code> is the escape sequence for
- <code> &</code>
- </UL>
-
- Note that ``escape sequence'' means that the given sequence of
- characters represents the single character in an HTML document and that
- the semicolon is required. The
- conversion to the single character itself takes place when the
- document is formatted for display by a reader. <P>
-
- There are additional escape sequences, such as
- a whole set of sequences to support
- 8-bit character sets (ISO 8859-1). For example:
-
- <UL>
- <LI> <code>ö</code> is the escape sequence for
- a lowercase <code>o</code> with an umlaut: ö
- <LI> <code>ñ</code> is the escape sequence for
- a lowercase <code>n</code> with an tilde: ñ
- <LI> <code>È</code> is the escape sequence for
- an uppercase <code>E</code> with a grave mark: È
- </UL>
-
- Many such escapes exist and are available in a <A NAME=2
- HREF="http://info.cern.ch/hypertext/WWW/MarkUp/ISOlat1.html">listing</A>
- from CERN. <P>
-
-
- <A NAME="InlineImage">
- <H2>Inline Images</H2>
- </A>
-
- NCSA Mosaic is can display X Bitmap (XBM) or GIF format images inside
- documents. <i>Each image
- takes time to process and slows down the initial display of the
- document</i>. Using a particular image multiple times in a document
- causes very little performance degradation compared to using the image only once. <P>
-
- <b>NOTE:</b> The <code><img></code> tag is an HTML extension
- first implemented in NCSA Mosaic. Currently it is not
- understood by most other World
- Wide Web browsers. <P>
-
- To include an inline image in your document, enter: <P>
-
- <PRE>
- <IMG SRC="filename.GIF">
- </PRE>
- <p>
-
- <img src="filename.GIF"> By default the bottom of an image is aligned with
- the text as shown in this paragraph.
- <p>
-
- <img align=top src="filename.GIF"> Include the <code>align=top</code>
- parameter if you want the viewer
- to align adjacent text with the top of the
- image as shown in this paragraph. The full inline image
- tag with the top alignment is:
- <pre>
- <IMG ALIGN=top SRC="filename.GIF">
- </pre>
- <p>
- If you have a larger image
- (i.e., one that fills most of your screen),
- you should insert an end of paragraph tag (<code><p></code>) before
- inserting the image parameter. End with another paragraph tag.
- (Or you might want to have the
- image open a new window, which is explained below.)
- </p>
-
- <A NAME="ExternalImage">
- <h3> External Images </h3>
- </A>
-
- You may want to have an image open as a separate document when a user
- activates a link on either a word or a smaller version of the image
- that you have inlined
- into your document. This is considered an external image and is particularly
- useful because (assuming you use a word for your hypertext link)
- you do not have
- any processing time degradation in the main document. Even if you include a
- small image in your document as the hyperlink
- to the larger image, the processing
- time for the ``postage stamp'' image is less than the full image.<p>
-
- To include a reference to a graphic in an external document, use
- <pre>
- <A HREF = "filename.gif">link anchor</A>
- </pre> <p>
- Make certain the image
- is in GIF, TIFF, JPEG, RGB, or HDF format.
-
- <A NAME="Troubleshooting">
- <H2>Troubleshooting</H2>
- </A>
- <UL>
- <LI> While certain HTML constructs can be nested (for example, you
- can have an anchor within a header), they cannot be overlapped.
- For example, the following is <i>invalid</i> HTML:
- <PRE>
- <h1>This is <a name="foo">invalid HTML.</h1></a>
- </PRE>
- Because many current HTML parsers aren't very good at handling
- invalid HTML, avoid overlapping constructs. <p>
-
- <LI> In NCSA Mosaic, when an <code><img></code> tag points at
- an image that does not
- exist or cannot be otherwise obtained from whatever server
- is supposed to be serving it, the NCSA logo is substituted.
- For example, entering <code><img href="DoesNotExist.gif">
- </code> (where
- "DoesNotExist.gif" is a nonexistant file) causes the following to
- be displayed: <iMG SRC="DoesNotExist.gif"> <P>
-
- If this happens to you, first make sure that the referenced
- image does in fact exist and that the hyperlink has the correct
- information in the link entry.
- Next verify that the file permission is set appropriately
- (world-readable).
- </UL>
-
- <A NAME="ExtendedExample">
- <H2>A Longer Example</H2>
- </A>
-
- Here is a longer example
- of a HTML document: <P>
- ________________________________________________________________________
- <PRE>
- <TITLE>A Longer Example</TITLE>
- <H1>A Longer Example</H1>
-
- This is a simple HTML document. This is the first
- paragraph. <P>
-
- This is the second paragraph, which shows special effects. This is a
- word in <I>italics</I>. This is a word in <B>bold</B>.
- Here is an inlined GIF image: <IMG SRC="myimage.gif">.
- <p>
-
- This is the third paragraph, which demonstrates links. Here is
- a hypertext link from the word <A HREF="subdir/myfile.html">foo</A>
- to a document called "subdir/myfile.html". (If you
- try to follow this link, you will get an error screen.) <P>
-
- <H2>A second-level header</H2>
-
- Here is a section of text that should display as a
- fixed-width font: <P>
-
- <PRE>
- On the stiff twig up there
- Hunches a wet black rook
- Arranging and rearranging its feathers in the rain ...
- </PRE>
-
- This is a unordered list with two items: <P>
-
- <UL>
- <LI> cranberries
- <LI> blueberries
- </UL>
-
- This is the end of my example document. <P>
-
- <address>Me (me@mycomputer.univ.edu)</address>
- </PRE>
- ________________________________________________________________________
- <p>
- <A NAME=37 HREF="/General/Internet/WWW/LongerExample.html">Click here</A>
- to see the formatted version.
- <p>
-
- <A NAME="MoreInfo">
- <H2>For More Information</H2>
- </A>
-
- More <A NAME=information>information</A> on HTML is available through the
- following hyperlinks. <P>
-
- <ul>
- <li><A HREF="/General/Internet/WWW/HTMLQuickRef.html">HTML Quick
- Reference Guide</a>, which gives a comprehensive listing of HTML codes
-
- <li>the official HTML <A NAME=3
- HREF="http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html">specs
- </A>
-
- <li>the in-development HTML <A NAME=6
- HREF="http://info.cern.ch/hypertext/WWW/MarkUp/HTML.html">RFC</A> (Request
- for Comments)
-
- <li>a description of <A NAME=4
- HREF="http://info.cern.ch/hypertext/WWW/MarkUp/SGML.html">SGML</a>,
- the Standard Generalized Markup Language
-
- <li>the <A NAME=5
- HREF="http://info.cern.ch/hypertext/WWW/Addressing/Addressing.html">URL
- (Uniform Resource Locator) specification</A>
-
- <li>the <A NAME=8
- HREF="http://info.cern.ch/hypertext/WWW/Provider/Style/Overview.html">style
- guide</A> for online hypertext document structures
-
- </ul>
- <p>
- ____________________________________________________________________
- <ADDRESS> A Beginner's Guide to HTML/ NCSA / pubs@ncsa.uiuc.edu </ADDRESS>
-
-
-
- </BODY></HTML>