WORLD WIDE WEB FREQUENTLY ASKED QUESTIONS››                      This is part 2 of a 2-part posting.›                   Part 2 begins with section 5 (providing›                information to the web). Part 1 should be the›                      previous posting in this thread.››   5.1: INTRODUCTION (TO PART 2): HOW CAN I PROVIDE INFORMATION TO THE WEB?›                                       ›   ›   Information providers run programs that the browsers can obtain›   hypertext from. These programs can either be WWW servers that›   understand the HyperText Transfer Protocol HTTP (best if you are›   creating your information database from scratch), "gateway" programs›   that convert an existing information format to hypertext, or a›   non-HTTP server that WWW browsers can access -- anonymous FTP or›   gopher, for example.›   ›   To learn more about World Wide Web servers, you can consult a www›   server primer by Nathan Torkington, available at the URL›   http://www.vuw.ac.nz/who/Nathan.Torkington/ideas/www-servers.html.›   ›   If you only want to provide information to local users, placing your›   information in local files is also an option. This means, however,›   that there can be no off-machine access.›   ›5.2: Obtaining Servers››   Servers are available for Unix, Macintosh, MS Windows, and VMS›   systems. If you know of a server for another operating system, please›   contact me.›   ›   See http://info.cern.ch/hypertext/WWW/Daemon/Overview.html for more›   information on writing servers and gateways in general.›   ›  5.2.1: UNIX SERVERS›  ›   NCSA httpd›          NCSA has released a server, known as the NCSA httpd; it is›          available at the URL ftp://ftp.ncsa.uiuc.edu/Web/ncsa_httpd.›          ›   CERN httpd›          CERN's server is available for anonymous FTP from info.cern.ch›          (URL is http://info.cern.ch/hypertext/WWW/Daemon/Status.html)›          and many other places. Use your local copy of archie to search›          for "www" in order to find a nearby site.›          ›   GN Gopher/HTTP server›          The GN server is unique in that it can serve both WWW and›          Gopher clients (in their native modes). This is a good server›          for those migrating from Gopher to WWW, although it does not›          have the server-side-script capabilities of the NCSA and CERN›          servers. See the URL http://hopf.math.nwu.edu/.›          ›   Perl server›          There is also a server written in the Perl scripting language,›          called Plexus, for which documentation is available at the URL›          http://bsdi.com/server/doc/plexus.html.›          ›  5.2.2: MACINTOSH SERVERS›  ›   There is a server for the Macintosh, MacHTTP, available at the URL›   http://www.uth.tmc.edu/mac_info/machttp_info.html.›   ›  5.2.3: MS WINDOWS AND WINDOWS NT SERVERS›  ›   HTTPS (Windows NT)›          HTTPS is a server for Windows NT systems, both Intel and Alpha›          -- based. It is available via anonymous FTP from emwac.ed.ac.uk›          in the directory pub/https (URL is›          ftp://emwac.ed.ac.uk/pub/https). (Be sure to download the›          version appropriate to your processor.) You can read a detailed›          announcement at the FTP site, or by using the URL›          ftp://emwac.ed.ac.uk/pub/https/https.txt.›          ›   NCSA httpd for Windows›          The NCSA httpd for Windows has most of the features of the Unix›          version, including scripts (which generate pages on the fly›          based on user input). It is available by anonymous FTP from›          ftp.ncsa.uiuc.edu in the Web/ncsa_httpd/contrib directory as›          the file whtp11a6.zip, or at the URL›          ftp://ftp.ncsa.uiuc.edu/Web/ncsa_httpd/contrib/whtp11a6.zip.›          ›   SerWeb›          A simple, effective server for Windows writtten by Gustavo›          Estrella. Available by anonymous ftp from›          winftp.cica.indiana.edu (or one of its mirror sites, such as›          nic.switch.ch), as the file serweb03.zip, in the directory›          /pub/pc/win3/winsock.›          ›          There is also a Windows NT version of SerWeb, available by›          anonymous FTP from emwac.ed.ac.uk as /pub/serweb/serweb_i.zip.›          ›   WEB4HAM›          Another Windows-based server, available by anonymous FTP from›          ftp.informatik.uni-hamburg.de as /pub/net/winsock/web4ham.zip.›          ›  5.2.4: MSDOS SERVERS›  ›   KA9Q NOS (nos11c.exe) is a internet server package for DOS that›   includes HTTP and Gopher servers. It can be obtained via anonymous FTP›   from one of the following sites:›   ››inorganic5.chem.ufl.edu›biochemistry.cwru.edu››   ›   ›  5.2.5: VMS SERVERS›  ›   CERN HTTP for VMS›          A port of the CERN server to VMS. Available at the URL›          http://delonline.cern.ch/disk$user/duns/doc/vms/distribution.ht›          ml.›          ›   Region 6 Threaded HTTP Server›          A native VMS server which uses DECthreads(tm). This is a›          potentially major performance advantage because VMS has a high›          overhead for each process, which is a problem for the›          frequently-forking NCSA and CERN servers that began life under›          Unix. A multithreaded server avoids this overhead. Available at›          the URL›          http://kcgl1.eng.ohio-state.edu/www/doc/serverinfo.html.›          ›   ›   ›  5.2.6: AMIGA SERVERS›  ›   NCSA's Unix server has been ported to the Amiga, and is bundled with›   the AMosaic browser. See the URL›   http://insti.physics.sunysb.edu/AMosaic/home.html for details.›   ›5.3: Producing HTML documents››   HTML is the simple markup system used to create hypertext documents.›   There are three ways to produce HTML documents: writing them yourself,›   which is not a very difficult skill to acquire, using an HTML editor,›   which assists in doing the above, and converting documents in other›   formats to HTML. The following three sections cover these›   possibilities in sequence.›   ›  5.3.1: WRITING HTML DOCUMENTS YOURSELF›  ›   You can write an HTML document with any text editor. Try the "source"›   button of your browser (or "save as" HTML) to look at the HTML for a›   page you find particularly interesting. The odds are that it will be a›   great deal simpler than you would expect. If you're used to marking up›   text in any way (even red-pencilling it), HTML should be rather›   intuitive.›   ›   A beginner's guide to HTML is available at the URL›   http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html. You can›   also find a plain text version (at the URL›   ftp://ftp.ncsa.uiuc.edu/ncsapubs/WWW/HTMLPrimer.txt) and a compressed›   Postscript version (at the URL›   ftp://ftp.ncsa.uiuc.edu/ncsapubs/WWW/HTMLPrimer.ps.Z). (Since the›   latter two are FTP URLs, you can fetch them by hand using FTP if you›   do not yet have a web browser.)›   ›   There is also a good set of HTML documentation available at the URL›   http://www.ucc.ie/info/net/htmldoc.html.›   ›   There is also an HTML primer by Nathan Torkington at the URL›   http://www.vuw.ac.nz/who/Nathan.Torkington/ideas/www-html.html.›   ›  5.3.2: HTML EDITORS›  ›   Of course, most folks would still prefer to use a friendlier,›   graphical editor. Some editors are WYSIWYG (What You See Is What You›   Get), or close to it; others simply assist you in writing HTML by›   plugging in the desired markup tags for you from a menu.›   ›   Fans of the EMACS editor can use EMACS and html-helper-mode , an EMACS›   "mode" for HTML editing (URL is http://www.reed.edu/~nelson/tools/).›   ›   There is also another Emacs HTML mode, html-mode.el (URL is›   ftp://ftp.ncsa.uiuc.edu/Web/elisp/html-mode.el).›   ›   For Microsoft Windows users, there is an editor called HTML Assistant›   with features to assist in the creation of HTML documents. It can be›   had by anonymous FTP from ftp.cs.dal.ca in the directory /htmlasst/.›   Read the README.1ST file in this directory for information on which›   files to download.›   ›   A WYSIWYG editor for the Web, *SoftQuad HoTMetaL*, is available for›   downloading at NCSA and other Mosaic server sites. Many mirror sites›   exist; if you can't get through to one, try another, don't give up!›   That's what mirror sites are for. (Also be sure to use the copy›   closest to you geographically if possible.)›   ›   Known mirrors:›     *›       ftp://ftp.ncsa.uiuc.edu/Mosaic/contrib/SoftQuad/sqhotmetal-1.0.tar.›       gz›     * ftp://ftp.ifi.uio.no/pub/SGML/HoTMetaL›     * ftp://sgml1.ex.ac.uk/SoftQuad›     * ftp://doc.ic.ac.uk/pub/packages/WWW/ncsa/contrib/SoftQuad›     *›       ftp://askhp.ask.uni-karlsruhe.de/pub/infosystems/mosaic/contrib/Sof›       tQuad›     * ftp://ftp.cs.concordia.ca/pub/www›       ›   You need a Sun SPARC or Microsoft Windows system and 6MB of disk (6MB›   of RAM minimum for MS Windows). Because it is context-sensitive,›   HoTMetaL guides users in creating new HTML documents and in cleaning›   up old ones. A Publish command changes appropriate SRC and HREF›   attributes from local paths to http locations. For more information,›   FTP the README file from the same directory, or send email to›   hotmetal@sq.com. A HoTMetaL Pro commercially supported version is›   available for purchase from SoftQuad and its resellers.›   ›   An editor for all X users: TkWWW (listed above under X browsers)›   supports WYSIWYG HTML editing; and since it's a browser, you can try›   out links immediately after creating them.›   ›   Also for X users, there is a package called htmltext which supports›   WYSIWYG HTML editing. More information is available at the URL›   http://web.cs.city.ac.uk/homes/njw/htmltext/htmltext.html.›   ›   For Macintosh users, there is evidently a near-WYSIWYG package called›   HTML Editor (URL is http://dragon.acadiau.ca:1667/~giles/HTML_Editor).›   ›   ›   Also for Macintosh users, the BBEdit HTML extensions allow the BBEdit›   and BBEdit Lite text editors for the Macintosh to conveniently edit›   HTML documents. (URL is›   http://www.uji.es/bbedit-html-extensions.html.) You can also obtain›   the extensions package by anonymous ftp from sumex-aim.stanford.edu as›   info-mac/bbedit-html-ext-b3.hqx.›   ›   There is an alternative BBEdit extension package available as well›   (URL is http://www.york.ac.uk/~ld11/BBEditTools.html). it is available›   by FTP from ftp.york.ac.uk in the directory›   /pub/users/ld11/BBEdit_HTML_Tools.sea.hqx.›   ›   NCSA's List of Filters and Editors, for which the URL is›   http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/faq-software.html#ed›   itors, mentions several editors, including two for MS Windows. In some›   cases, the "editor" amounts to a set of macros for an existing word›   processor, which can provide a near-WYSIWYG environment.›   ›   Note that this URL contains uppercase and lowercase letters; certain›   operating systems won't allow mixed case on the command line, or will›   only allow it if it is quoted (VMS), so if you are launching Lynx or›   another client and specifying a URL at the command line, try quoting›   the URL in double-quotes ("URL").›   ›   Another option, if you have an SGML editor, is to use it with the HTML›   DTD .›   ›  5.3.3: CONVERTING OTHER FORMATS TO HTML›  ›   There is a collection of filters for converting your existing›   documents (in TeX and other non-HTML formats) into HTML automatically,›   including filters that can allow more or less WYSIWYG editing using›   various word processors:›   ›   Rich Brandwein and Mike Sendall's List at CERN. The URL is›   http://info.cern.ch/hypertext/WWW/Tools/Filters.html.›   ›   (Note that this URL contains uppercase and lowercase letters; certain›   operating systems such as VMS require you to quote mixed-case URLs›   when launching a borwser from the command line. This is NOT a bug in›   the browser.)›   ›   There is also a Word for Windows template for writing HTML documents,›   available at the URL http://www.gatech.edu/word_html/release.htm.›   ›5.4: How do I publicize my work?››   There are several things you can do to publicize your new HTML server›   or other offering:›     * Submit it to the NCSA What's New Page at the URL›       http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/whats-new.html›       (see the page for details on how to submit your listing!).›     * Post it to the newsgroup comp.infosystems.announce. Please read›       the group first to get a feel for the contents. You should not›       post to comp.infosystems.www.users,.misc,.providers, etc., but if›       you feel compelled to do so, please choose .misc as announcements›       are of interest to both providers and users (and those who wear›       both hats).›     * Submit it to the maintainers of various catalogs, such as the WWW›       Virtual Library (at the URL›       http://info.cern.ch/hypertext/DataSources/bySubject/Overview.html)›       and the ALIWEB index (at the URL›       http://web.nexor.co.uk/aliweb/doc/aliweb.html).›       ›5.5: Can I buy space on an existing server?››   Yes, you can. A list of sites offering WWW space for lease is›   available (at the URL http://union.ncsa.uiuc.edu/www/leasing.html ).›   ›  5.6.1: HOW DO I SET UP A CLICKABLE IMAGE MAP?›  ›   ›   ›   There are really two issues here: how to indicate in HTML that you›   want an image to be clickable, and how to configure your server to do›   something with the clicks returned by Mosaic, Chimera, and other›   clients capable of delivering them.›   ›   You can read about image maps and the NCSA server at the URL›   http://hoohoo.ncsa.uiuc.edu/docs/setup/admin/Imagemap.html.›   ›   Using imagemaps requires that you create a map file; you can do this›   by hand or with a WYSIWYG tool. I wrote Mapedit (URL is:›   http://sunsite.unc.edu/boutell/mapedit/mapedit.html ), which is such a›   tool for Microsoft Windows and the X Window System. Other tools are›   available. (URLs, anyone?)›   ›   _Important Note:_ Creating imagemaps requires a cooperative server›   administrator and a real web server. Don't waste time making maps›   before making sure you have the necessary tools to deliver them.›   ›  5.6.2: HOW DO I MAKE A "LINK" THAT DOESN'T LOAD A NEW PAGE?›  ›   ›   ›   Such links are useful when a form is intended to perform some action›   on the server machine without sending new information to the client,›   or when a user has clicked in an undefined area in an image map; these›   are just two possibilities.›   ›   Rob McCool of NCSA provided the following wisdom on the subject:›   ››Yechezkal-Shimon Gutfreund (sg04@gte.com) wrote:›: Ok, here is another bizzare request from me:››: I am currently running scripts which I "DO NOT" want to return›: any visible result. That is, not text/plain, not text/HTML, not›: image/gif. The entire results are the side effects of the›: script and nothing should be returned to the viewer.››: It would be nice to have an internally supported null viewer›: so that I could do this, more "cleanly" (ok, ok, I hear your groans).››   ›   ›   HTTP now supports a response code of 204, which is no operation. Some›   browsers such as Mosaic/X 2.* support it. To use it, make your script›   a nph script and output an HTTP/1.0 204 header. Something like:›   ›   HTTP/1.0 204 No response Server: Myscript/NCSA httpd 1.1›   ›   (You can learn more about nph scripts from the NCSA server›   documentation at the URL http://hoohoo.ncsa.uiuc.edu/docs.)›   Essentially they are scripts that handle their own HTTP response›   codes.›   ›  5.6.3: WHERE CAN I LEARN HOW TO CREATE FILL-OUT FORMS?›  ›   You can read about the Common Gateway Interface (at the URL›   http://hoohoo.ncsa.uiuc.edu:80/cgi/). In addition to documenting the›   standard interface for which scripts can now be written for both NCSA›   and CERN-derived servers, these pages also cover HTML forms and how to›   handle the results on the server side. See the section on email forms›   for a simple solution to the most commonly desired form.›   ›    5.6.3.1: How can I create hidden fields in forms (keeping state)?›    ›   Use INPUT TYPE=hidden. An example:›   ››<INPUT TYPE=hidden NAME=state VALUE="hidden info to be returned with form">››   By now, most if not all browsers can handle the hidden type. Note that›   "hidden" doesn't mean "secret"; the user can always click on "view›   source".›   ›    5.6.3.2: How can users send me email through their browsers?›    ›   If you have access to the server's configuration files, or if your›   server administrator permits users to create their own CGI scripts,›   you can arrange it. I've written a simple email forms package (URL is:›   http://siva.cshl.org/email/index.html), which does it in ANSI C. There›   is also a package floating around in Perl (URL, anyone?).›   ›  5.6.4: HOW DO I COMMENT AN HTML DOCUMENT?›  ›   ›   ›   Use the <!-- tag at the beginning of EACH line commented out; close›   this for EACH line with the --> tag. Note that comments do not nest,›   and the sequence "--" may not appear inside a comment except as part›   of the closing --> tag.›   ›   You should _not_ try to use this to "comment out" HTML that would›   otherwise be shown to the user, since some browsers (notably Mosaic)›   will still pay attention to tags inside the comment and close it›   prematurely.›   ›   _Thanks to Joe English for clearing up this issue._›   ›  5.6.5: HOW CAN I CREATE DECENT-LOOKING TABLES AND STOP USING <PRE>... </PRE>?›  ›   Tables are a standard feature in HTML Level 3, a new version of HTML.›   Unfortunately, they are at present implemented only by the Viola and›   Emacs-W3 browsers, to my knowledge.›   ›   _However_, there is a way to use HTML Level 3 tables now and convert›   them automatically to HTML, allowing you to design proper tables and›   install those pages directly when table support arrives in the›   majority of clients. You can do this using the html+tables package, by›   Brooks Cutter (bcutter@paradyne.com), which is available for anonymous›   ftp from sunsite.unc.edu in the directory›   pub/packages/infosystems/WWW/tools/html+tables.shar. This package›   requires the shell language Perl, which is primarily used on Unix›   systems but is also available for other systems (such as MSDOS›   machines). html+tables accepts HTML Level 3 and outputs html using the›   <PRE>...</PRE> construct to represent tables, allowing you to write›   HTML Level 3 now, knowing that it will look better when clients are›   ready for it.›   ›  5.6.6: WHAT IS HTML LEVEL 3 AND WHERE CAN I LEARN MORE ABOUT IT?›  ›   HTML Level 3, also known as HTML+, is an enhanced version of HTML›   designed to address some of the limitations of HTML. HTML Level 3›   supports true tables, right-justified text, centered text, line breaks›   that do not double space, and many other desired features.›   ›   However, most clients support only a handful of HTML Level 3 features›   (such as forms in Mosaic) at this time.›   ›   You can access information about new developments in HTML at the CERN›   server (at the URL›   http://info.cern.ch/hypertext/WWW/Markup/Markup.html ).›   ›   (HTML Level 1 is the original version. HTML Level 2 is essentially the›   same, but with the addition of forms.)›   ›  5.6.7: HOW CAN I MAKE TRANSPARENT GIFS?›  ›   Transparent GIFs are useful because they appear to blend in smoothly›   with the user's display, even if the user has set a background color›   that differs from that the developer expected.›   ›   There is a document explaining transparent GIFs available at the URL›   http://melmac.corp.harris.com/transparent_images.html. You can fetch›   the program giftrans by anonymous ftp from ftp.rz.uni-karlsruhe.de at›   the path /pub/net/www/tools/giftrans.c.›   ›   There is also a utility for the Macintosh, Transparency (URL is:›   http://www.med.cornell.edu/~giles/projects.html#transparency).›   ›  5.6.8: HOW COME MAILTO: URLS DON'T WORK?›  ›   The mailto: URL is an innovation found in Lynx and a few other›   browsers. It is not yet found in Mosaic, the most popular browser.›   Hopefully it will be present in future versions. In the meantime, you›   can set up forms which send mail to you; there is documentation on›   this at the URL http://siva.cshl.org/email/index.html.›   ›  5.6.9: HOW CAN I RESTRICT AND CONTROL ACCESS TO MY SERVER?›  ›   All major servers have features that allow you to limit access to›   particular sites, and many clients have authentication features that›   allow you to identify specific users. There is a tutorial on security›   and user authentication with the NCSA server and Mosaic available,›   written by Marc Andreessen (URL is›   http://wintermute.ncsa.uiuc.edu:8080/auth-tutorial/tutorial.html). See›   your server documentation for further information.›   ›  5.6.10: WHICH FORMAT IS BETTER FOR WWW IMAGE PURPOSES, JPEG OR GIF?›  ›   ›   ›   JPEG does a better job with realistic images such as scanned›   photographs. Most browsers cannot handle inline JPEGs, however, so you›   must link to them as external images (using a regular &ltA HREF...>›   instead of <IMG SRC...>.›   ›   GIF does a better job with crisp, sharp images, such as those›   typically used to construct buttons, graphs and the like. All browsers›   that can display graphics at all can display GIFs inline.›   ›  5.6.11: HOW CAN I MIRROR PART OF ANOTHER SERVER?›  ›   Scripts are available to do this, but at this time they are not very›   friendly to the server you are attempting to mirror; their behavior›   resembles that of the more poorly written WWW robots. If you are›   trying to improve access times to a distant server, you will likely›   find the "proxy" capabilities of CERN's WWW server to be a more›   effective and general solution to your problem.›   ›  5.6.12: HOW CAN I KEEP ROBOTS OFF MY SERVER?›  ›   Programs that automatically traverse the web can be quite useful, but›   have the potential to make a serious mess of things. Every so often›   someone will write a "depth-first" searching robot that brings servers›   to their knees. See the section on writing robots (4.10) for details.›   ›   Fortunately, most robots on the web follow a simple protocol by which›   you can keep them off your server if you wish, or keep them out of›   portions of your server which are robot traps (ie, they contain an›   infinite number of possible links). Read the document World Wide Web›   Robots, Wanderers and Spiders (URL is:›   http://web.nexor.co.uk/mak/doc/robots/robots.html) and learn about the›   emerging standards for exclusion of robots from areas in which they›   are not wanted. You can also read about existing robots there,›   including useful cataloging robots you probably do _not_ want to keep›   off your server.›   ›                      6: WHAT NEWSGROUPS DISCUSS THE WEB?›                                       ›   You can find discussion of World Wide Web topics in three newsgroups,›   and one newsgroup which will soon be removed:›   ›   comp.infosystems.www.users›          A forum for the discussion of WWW client software and its use›          in contacting various Internet information sources. New user›          questions, client setup questions, client bug reports,›          resource-discovery questions on how to locate information on›          the web that can't be found by the means detailed in the FAQ›          and comparison between various client packages are among the›          acceptable topics for this group. Please specify what browser›          and what system type (Windows, Mac, Unix, etc.) your post is›          about if you are asking questions about a specific program.›          ›   comp.infosystems.www.providers›          A forum for the discussion of WWW server software and the use›          of said software to present information to users. General›          server design, setup questions, server bug reports, security›          issues, HTML page design and other concerns of information›          providers are among the likely topics for this group.›          ›   comp.infosystems.www.misc›          A forum for general discussion of WWW (World Wide Web)- related›          topics that are NOT covered by the other newsgroups in the›          hierarchy. This will likely include discussions of the Web's›          future, politicking regarding changes in the structure and›          protocols of the web that affect both clients and servers, et›          cetera.›          ›   comp.infosystems.www (DEFUNCT)›          The old catch-all newsgroup, which may still exist on your›          system but will be removed on September 7th, according to David›          Tale, moderator of news.announce.newgroups.›          ›   ›   ›                            7: I WANT TO KNOW MORE›                                       ›   ›   ›   To find out more, use the web. This FAQ hopefully provides enough›   information for you to locate and install a browser on your system. If›   you have system specific questions regarding FTP, networking and the›   like, please consult newsgroups relevant to your particular hardware›   and operating system!›   ›   Once you're up and running, you may wish to consult the World Wide Web›   Primer by Nathan Torkington. It is available at the URL›   http://www.vuw.ac.nz/who/Nathan.Torkington/ideas/www-primer.html.›   ›   Later you may return to this FAQ for answers to some of the more›   advanced questions. I encourage you to check out the changes listed›   early in the document each time the FAQ appears.›   ›                                  8: CREDITS›                                       ›     * Thomas Boutell _boutell@netcom.com_›     * Nathan Torkington _Nathan.Torkington@vuw.ac.nz_›     * Marc Andreessen _marca@ncsa.uiuc.edu_›     * Tony Johnson››