by Mark Brown
They say that the camera never lies. A photograph is a record of a real scene as it was captured by the camera's lens.
On the other hand, two artists never paint the same scene the same way. Every element is subject to the artist's interpretation. One artist might paint a photo-realistic image that's almost sharper than reality; another might render an abstract smear that communicates mood more accurately than it portrays the scene. They might move, add, remove, or alter objects or change lighting to suit their depictions of the scene.
The World Wide Web works more like painting than it does like taking photographs. A Web server "serves up" a page over the Internet, and a Web browser program interprets it. The results may be almost as different as the two painting styles described above. This is the central, surprising truth about the World Wide Web: what you see on a Web page is described, not defined, by its HTML code. It is up to the user's browser program to render it in its final form.
Many new Web developers are shocked to discover that they have so little control over the final appearance of their pages. But, for better or worse, that's how the Web works. If you want to create Web pages that can be viewed accurately by a wide range of WWW users, you're going to have to be aware of the different server and browser programs that are out there and how they work together.
In this chapter, you learn about the following:
The World Wide Web has a client/server architecture. This means that a client program running on your computer (your Web browser) requests information from a server program running on another computer somewhere on the Internet. That server then sends the requested data back over the Net to your browser program, which interprets and displays the data on your screen. Figure 2.1 shows the whole process graphically. The following steps explain the process:
Figure 2.1 : This is what happens when you view a page on the World Wide Web.
| Note |
Many computer networks include a security mechanism called a firewall. A firewall is software (often combined with specialized hardware) that creates a barrier to keep unauthorized outside users from accessing a site. If a system is equipped with a firewall, inside users must use proxy programs to access the Internet. Although this adds a couple of steps, the fundamental process of transferring data back and forth between client and server is essentially unchanged. |
| Note |
You can also set up a server to run a Web site over a LAN (local area network) without connecting it to the outside world at all. This is sometimes referred to as an Intranet. In this scenario, only those connected directly to the LAN are able to access the pages on the server. Many companies use a setup like this for distributing internal information to their employees. |
To browse the Web, you need a client computer. There are two basic requirements for this machine: it must have a connection to the Internet and must be capable of running a Web browser program.
The Internet connection can be hard-wired, or it can be a dial-up phone connection via modem to an Internet service provider (ISP). You're most likely to have the former at work or school and the latter at home. The only difference you will notice between the two is speed; otherwise, they work identically.
There are Web browser programs for just about any computer you can name, from dumb text-only terminals running on mainframes to off-brand personal computers, such as the Amiga. (I'll list and discuss the most popular browser programs later in this chapter.)
On the content-provider side of things, you need a server computer.
This machine has requirements similar to those of the client computer:
it must be connected to the Internet and must be able to run a
Web server program.
| Tip |
A Web server program is often called an HTTPD, for HyperText Transfer Protocol Daemon. Daemon is computerese for a program that runs unseen in the background. |
However, a Web server needs a more robust Internet connection than a Web client does. A server should ideally be hooked up to the Internet via a fast dedicated T1 or T3 line that remains connected all the time. Otherwise, people trying to access your Web site will often find that it just isn't there.
It is possible (though excruciatingly slow) to run a Web site
on a dial-up line, especially if you can find an Internet service
provider who will let you stay dialed in 24 hours a day without
disconnecting you. However, you must make sure that your ISP can
assign a permanent IP address to your machine-not a new IP address
each time you connect. Otherwise, people won't even be able to
find your site.
| Note |
A good intermediate solution to the direct vs. dial-up problem is an ISDN line. A sort of super fast digital phone line, an ISDN line costs more than a regular phone line but much, much less than a dedicated T1 or T3 line. It also requires a special interface card for your computer. ISDN lines are offered by most phone companies in urban areas and university towns, but you'll need to find an ISP that can provide an ISDN connection too. Contact the business office of your local phone company for details. |
HTTPD server software is available for a wide variety of computers (see fig. 2.2). Surprisingly, server computers don't have to be very powerful; serving up Web content is simply not that demanding. More of a concern is having a multithreaded, multitasking operating system so that the server can handle several tasks at once without bogging down. Storage is a concern, however, because Web sites are notorious for growing without limit.
An HTTP connection is said to be stateless. That is, no permanent connection is maintained between the server and the client. A request is made, and the connection is broken. Then a response is sent back, and the connection is broken again. This process is repeated for every request and often even for parts of a request. Programmers refer to this as a query-response model of interaction. It's the reason your browser program always seems to be saying "Waiting for reply…" in its status display line. (See the message at the bottom of fig. 2.3.)
A browser's request for information takes the form of a URL (Uniform Resource Locator), which is also referred to as a page's address or location. URLs almost always look something like this:
http://www.somesite.net/path/webpage.html
| Tip |
A URL is always a single, unbroken line of text with no spaces. |
Web browsers generally display the URL of the Web page currently being viewed near the top of the window (see fig. 2.3).
Here's a real world example of a URL, taken from figure 2.3:
http://www.microsoft.com/msoffice/freestuf/msword/download/ia/default.htm
The "http://" portion of the URL indicates that the
browser has requested a transfer via HTTP protocol; that is, it
wants a Web page. "www.microsoft.com" is the domain
name of the server being queried; in this case, it's the Web server
at Microsoft. The "msoffice/freestuf/msword/download/ia/"
portion of the URL is the path name on the server's hard drive
for the file you want. (Fortunately, this example is of one of
the longer path names you're likely to run into on the Web.) "default.htm"
is the name of the actual HTML file on the server; it's what is
being displayed on the screen in figure 2.3.
| Tip |
If the protocol portion of a URL is https:// or snews://, it means that the connection is secure. In Netscape, this will be confirmed by the presence of an unbroken security key in the lower left-hand corner of the screen. |
URLs can reference not only Web pages, but also just about any
service on the Internet, including FTP, Gopher, WAIS, Usenet,
and Telnet. You can even load in a file from your own computer!
Table 2.1 shows the syntax for the various types of sites that
can be accessed via a Web browser.
| URL Syntax | Type of Access |
| file:// | a file on your local computer |
| ftp:// | an FTP server |
| gopher:// | a Gopher server |
| http:// | a Web page |
| news:// | a Usenet newsgroup |
| telnet:// | a connection to a Telnet site |
| WAIS:// | a WAIS server |
The domain name portion of a URL may include a colon followed by a port number, like this:
http://www.somesite.net:80/path/webpage.htm
This tells the server to access the site via a specific assigned
port.
| Tip |
Port 80 is the default port defined in the HTTP specification. If not given, it is assumed. |
Web page file names usually end in .htm or .html to indicate that they are HTML content files. Many home pages don't have path names or file names at all. Their URLs are in a very abbreviated format:
http://www.somesite.net
These addresses access a page that is stored in the server's root directory; that is, they don't need a path name because they aren't stored in a subdirectory. Most servers also assume a default file name for the home page, such as hompage.html or index.htm. If no page file name is specified, the server will automatically serve up the default page.
URLs can point to other types of files than HTML Web pages, of course. For example, the URL http://www.somesite.net/logo.gif would display a GIF image file. http://www.somesite.net/path/program.zip would, depending on how your browser is configured, prompt you to save the specified ZIP file to disk or would decompress the file and store the resulting program files to disk.
Sometimes you may see a URL that looks something like this:
http://www.somesite.net/cgi-bin/findit&toad+frog
Servers can include gateways, which enable them to run application programs called CGI (Common Gateway Interface) scripts or programs. These are, in most ways, just like any other programs run by a computer. Depending on the machine and the gateway, CGI-bin (bin for binary) programs might be written in C, C++, BASIC, or the PERL scripting language. An URL like the one above instructs the server to run the CGI program called findit using the data toad and frog as inputs. In this example, it would be a fair guess that the server program, findit, was some sort of indexing program and that the user had instructed it to find references in its database to toads and frogs.
Some hyperlinks may reference a relative URL; that is, one in the same path name on the same server as the page currently being viewed. For example, if the current page is http://www.somesite.net/path/thispage.html, a relative link to thatpage.html would load in the page whose absolute address is http://www.somesite.net/path/thatpage.html. This technique not only saves page creation time and space on the server, but it also makes it very easy to move all of the files associated with a Web site to a new directory or even to a new machine. Only the references to the home page need to be changed; relative URLs remain the same.
A Web server computer runs an HTTPD (HyperText Transfer Protocol Daemon) program (see fig. 2.4). The history behind the development of HTTP is told in chapter 1, "Introducing the World Wide Web." This section will concentrate on how Web servers use HTTP to communicate with browser clients.
When you analyze what a server does, you begin to fully realize just how much of the look and feel of the World Wide Web is in the browser program.
The browser client strips an URL down to its component parts: protocol, address, path name, and file name. From the protocol portion, it determines how it is going to interact with the server that it's addressing and how to display the data it will receive. It then calls the address contained in the URL and waits for a response from the server.
Once the server realizes that a request is coming through, it likewise checks the URL for the connection protocol (e.g., http:// for a Web page). It takes the path name and file name that it has been given, finds them on its hard drive, and sends the data off to the browser using the correct protocol.
Then it's the browser's turn again. This time it gathers in, interprets, and properly displays the data it has received.
It probably seems as if there is a lot more for the browser to do in this process than there is for the server, and in the case of a simple transaction, such as viewing a Web page, that's probably true. But there's much more than that going on in the background.
For example, if there's an error somewhere along the way-such as a request for a page that doesn't exist-the server has to send back the proper error message. If the user has requested an action that requires running a CGI program, the server has to load and run the program. This process usually means creating a custom HTML page "on the fly" that contains the results of the program's action, then sending that back to the browser.
Then, too, every data file transmitted by the server has to be properly identified by type and tagged with the appropriate MIME (Multipurpose Internet Mail Extension) data type header so the browser will know what to do with it. Most Web pages include a mix of HTML formatted text, GIF and JPEG graphics, and maybe even audio and video clips; each must be properly tagged, or the browser won't know how to interpret the pieces when they arrive.
Today's Web servers also include all kinds of esoterica-for example, data encryption and client authentication. These take up a great deal of the server's time, too.
Factor in the fact that a server is often handling requests from
hundreds of clients at any one time, and you'll see that there's
more than enough going on to keep it busy.
| Tip |
For more information on servers, check out the Usenet newsgroups comp.infosystems.www.servers.misc, .mac, .ms-windows, and .unix. |
The HyperText Transfer Protocol (HTTP) was designed to be quick, simple, and nonintrusive. The connection between a server and a client program (or agent) is temporary and must be reestablished for every data transfer.
The HTTP specification incorporates a whole set of methods that are used to perform the tasks associated with servicing a Web site, including information retrieval, searching, front-end updating, and annotation. The specification is open-ended, so additional functionality can be added without making the whole Web obsolete.
As discussed previously, messages are passed in a format that is similar to Internet Mail and the Multipurpose Internet Mail Extensions (MIME); gateways enable browsers to request the execution of CGI applications on the server hardware; and communication is possible with other Internet protocols, such as SMTP, NNTP, FTP, Gopher, and WAIS.
HTTP is, like these earlier protocols, a TCP/IP protocol. However,
it can be implemented on top of any other protocol implementation
that can communicate over the Internet or on other networks, including
LANs.
| Tip |
The current version of the HTTP protocol specification can be found at the site maintained by the HTTP Working Group at http://www.ics.uci.edu/pub/ietf/http/. |
Almost any computer platform that you can name (and some you probably can't) can act as a Web server. There are HTTPD server programs for systems as varied as multimillion-dollar mainframes and PCs costing under $1000.
Which one is best? That's a question that is highly subjective, and it's certainly beyond the scope of this book. A more important question might be, "Do I need an HTTPD server program at all?"
If you usually hook up to the Web through an Internet service provider (ISP) and are thinking about setting up a personal Web site, the answer is almost certainly no! What you need is an account on somebody else's Web server, probably that of your ISP. Most ISPs offer a place for your own home page for little or nothing if you're already using their dial-up services. For example, my local ISP charges me $30 a month for unlimited Internet access and includes a 10 megabyte UNIX account on which I can keep my own World Wide Web pages.
If you think about it, this is an incredible bargain. For $1 a
day-which is less than I pay for cable TV-I maintain a Web site
that can be seen by anyone in the world, 24 hours a day! And they
take care of all the headaches of setting up and configuring the
server, maintaining the site, and handling glitches and bugs.
It's great. All I have to do is develop the content for my site,
write it in HTML, and upload it to my provider.
| Tip |
For an example of what kind of site you can set up using somebody else's Web server, check out my personal Web site at http://www2.giant.net/people/mbrown. |
Even small- to medium-sized companies might want to consider having
an ISP host their sites rather than setting up their own Web server.
It can mean a major investment of both time and money to set up
a server computer, hook it up via a permanent T1 or T3 land line,
install the HTTPD software, and maintain all of that hardware
and software over time. If your needs are moderate, having an
ISP take care of all that for you can be a major headache reliever.
| Tip |
You can find a searchable list of Internet service providers on the ISP Yellow Pages site at http://www.index.org/. |
However, if you are developing Web pages for a college or major corporation, you'll probably want to run your own site. This is the best way to go if your site:
If any of these criteria describe the site you want to set up, then pick a computer platform and HTTPD server software that match your requirements.
It is beyond the scope of this book to review all of the many
HTTPD servers that are currently available; nonetheless, I can
discuss the ones that are the most popular. Although popularity
is not exclusively determined by quality-price and compatibility
are certainly major issues as well-it can serve as a good measure
of which server programs are already working for a large number
of sites.
| Note |
The server use statistics in this section were taken from the server survey data at http://www.mirai.com/survey and from the Spry Webcrawler statistics at http://www.webcrawler.com/WebCrawler/Facts/WebFacts.html. |
Accurate statistical data about Web server usage is hard to come by. Most is based on random samplings of sites or on volunteer surveys, which can be highly skewed by inaccurate survey samples. But a comparison of the best data currently available on the Web seems to lead to the following conclusions about which computer platforms are probably the most popular Web servers:
This breakdown is shown graphically in the pie chart in figure 2.5.
A little over a year ago, more than 80 percent of the servers on the Web were UNIX-based. The shift shown in figure 2.5 certainly reflects two current trends: The rapid growth of the World Wide Web has moved it beyond the confines of academia and corporate America, where UNIX is most popular, and there has been, in the last year, a proliferation of HTTPD software for platforms other than UNIX.
Let's take a look at specific servers.
One of the major reasons for UNIX's predominance has been the number of freely distributable HTTPD server programs available for it. CERN HTTPD and NCSA HTTPD have historically been the two most popular server programs on the Web, and they remain at or near the top of the list.
However, a plethora of new server programs has been introduced in the past year, and some of them are gaining market share quickly. Although there are a few new freebies-Apache, for instance-many of the fastest-growing servers are commercial packages from such companies as Netscape, Quarterdeck, and Open Market.
There are many good reasons for the fast growth of commercial Web server programs. For the price, those buying commercial servers get the peace of mind that comes with knowing that the product is fully supported, not freeware with a nebulous cloud of hobbyist developers working on it in their spare time. Then, too, these products are finished goods; they don't need to be compiled to run and are packaged with complete documentation and a full set of additional Web development software tools.
Further, commercial servers usually offer additional functionality that just isn't found in freeware servers, such as encryption and security. And finally, most of the current growth of the Web can be directly attributed to the addition of many new commercial sites. Unlike the personal and academic sites that preceded them, commercial sites aren't scared off by the $400-$5,000 price tag that commercial server software carries.
Table 2.2 lists the most popular servers on the Web, as nearly as can be determined by current data.* Figure 2.6 shows the same data graphically.
| Server | Availability | Platform(s) | |
| NCSA | Free | UNIX/Win | |
| Apache | Free | UNIX | |
| Netscape | Commercial | UNIX/WinNT | |
| CERN HTTPD | Free | UNIX | |
| WebSTAR/MacHTTP | Comm/Free | Macintosh | |
| Others | Comm/Free | Varied | |
| * Source: Web Servers Survey Version 2.0, January 1996, by Paul E. Hoffman, Proper Publishing, http://www.proper.com/. | |||
There are, of course, a great many more HTTPD server programs
available than those shown in table 2.2. Table 2.3 lists HTTPD
server programs for a variety of platforms. To find out more about
any of these servers, check out Paul Hoffman's Server Comparison
Chart on the Web. This site contains a wealth of data for anyone
who is thinking about establishing a presence on the World Wide
Web, including hypertext links to the publishers of most of the
Web server programs listed in table 2.3. Its location is http://www.proper.com/www/servers-chart.html.
| Platform | Server |
| Amiga | Amiga Web Server |
| AS/400 | Server/400 |
| Macintosh | CL-HTTP, FTPd, httpd4Mac, MacHTTP, WebSTAR |
| Novell | SiteBuilder, Webware |
| OS/2 | GoServe |
| UNIX | Apache, Boa, CERN, CL-HTTP, GN, NaviServer, NCSA, Netscape Commerce, Netscape Communications, Open Market Secure WS, Open Market WebServer, Phttpd, SafetyWEB UNIX, Spinner, Spry Web UNIX, TEAMate, WN |
| VM/CMS | Webshare |
| VMS | CERN, Purveyor, Region 6 |
| Windows 3.1 | FrontPage, Quarterdeck |
| Windows 95 | Alibaba, Commerce Builder, Communications Builder, FolkWeb, FrontPage, Purveyor, Quarterdeck WebServer, SAIC, WebQuest, WebSite |
| Windows NT | Alibaba, Commerce Builder, Communications Builder, FolkWeb, FrontPage, HTTPS, Microsoft's Internet Information Server, NaviServer, NetPublisher, Netscape Commerce, Netscape Communications, Purveyor, Quarterdeck, SafetyWEB NT, SAIC, Spry Web NT, WebQuest, WebSite |
To a large degree, the Web is what your Web browser makes it. Because Web pages are written in HTML and because HTML is subject to interpretation, your browser profoundly affects the appearance of Web pages and, consequently, your impression of the World Wide Web as a whole.
Figure 2.7 shows the same Web page as viewed by three different browser programs: the all-text UNIX Lynx browser (upper left), an older Windows browser called Cello (upper right), and Netscape Navigator 2.0 (lower right). The fourth image (lower left) is the same page displayed by Netscape 2.0 with customized color and font settings. You can see how differently various browsers can interpret the same page and how significant user settings are in the outcome.
That's why it's important to make sure you have a good browser program (see fig. 2.8) if you're going to develop HTML documents for the World Wide Web. You want to make sure that your viewers are seeing the same pages you are.
| Note |
As a sort of experiment, you can simulate a Web browser program by Telneting into a Web site and executing the same command by hand that a browser would. Perform the following steps:
|
| Tip |
For more information on Web browser programs, check out the Usenet newsgroups comp.infosystems.www.browsers.misc, .mac, .ms-windows, and .X. |
HTML is not intended to be an all-encompassing, all-powerful page layout environment. HTML describes a page's look by using markup tags to indicate the relative position of elements on the page. For example, you can specify which lines of text are headings and their level of importance. You can show where in the text an in-line image should appear and whether certain blocks of text should appear with a particular type of formatting. You can even create tables and forms. With some of the most recent versions of HTML, you can create frames in which different parts of pages are displayed, put up graphic background wallpaper, and change the color of text on the fly.
HTML cannot, however, determine which font, font size, or color will be used to display text; what the screen background color will be; how the colors in graphics will be interpreted; or any of a wide variety of other variables that are at the mercy of browser programs or the users' settings of various options in their browser programs.
"Why doesn't HTML give a page creator more control?" you ask.
HTML's main appeal is that it is easy to learn and easy to use. Ease of implementation was, in fact, the major design criterion for HTML, and it worked. A recent survey of Web page creators found that over half of them learned the basics of HTML in under three hours, and another quarter took only six hours. Most said that a good book (like this one!) and the Web itself were the only tools they needed to begin creating Web pages.
HTML was also designed to be compatible across a wide range of machines, from text-only UNIX terminals to the flashiest Silicon Graphics workstation. To a large degree, that goal has been met, too. Although there will certainly be some differences in the same Web page viewed on different machines with different browsers, the results will likely be similar enough and acceptable enough to convey the information presented in the manner intended by the page's creator.
The responsibility for making sure this happens rests squarely
on the shoulders of the Web developer-you! Properly applied, HTML
can make your pages look good on a wide variety of platforms.
The more aware you are of the differences in Web browsers, the
better you'll be able to make sure your pages look good on all
(or at least most) of them.
| Note |
If you really want the pages you put on the Web to retain their original look and feel, you might want to consider making them available as PDF (Portable Document Format) files. A lot of companies and organizations do, from Adobe Systems to the IRS. A PDF file can't be read by a Web browser though-it needs an external viewer program. Adobe Acrobat is the most popular PDF format on the Web today. You can get information about Acrobat (and download a free viewer) from the Adobe Web site at http://www.adobe.com. |
So which Web browser clients are the most popular? That's one with an easy answer. The most popular Web browser today is Netscape Navigator, which is used by over 80 percent of those cruising the Web. Other browsers don't account for over four percent of the market each.
Does this mean that you can, with impunity, develop only for Netscape and ignore the rest? In a word, no. First of all, there are several different versions of Netscape Navigator out there, running on UNIX, Windows, Windows 95, and Macintosh platforms. If you want to use some of the latest and greatest Netscape features-such as frames -you'll leave behind the three-quartersor more of your Netscape audience who are, as of this writing, still using Netscape 1.1. (See chapter 15, "Netscape-Specific Extensions to HTML.") And the 20 percent of Web users who don't use Netscape Navigator are a sizable chunk of your audience too. You don't want to leave them out in the cold, do you?
Table 2.4 should give you some idea of the wide variety of client
programs that are out there browsing the Web.
| Platform | Browser | Comments |
| AMIGA | Amosaic | Based on NCSA Mosaic. FTP from aminet sites in pub.aminet.comm.net. Home page at http://insti.physics. sunysb.edu/AMosaic/home.html. FAQ at http://www.phone.net/ATCPFAQ/amosaic.html. |
| AMIGA | Amiga Lynx | Home page at http://www.fhi-berlin.mpg.de/amiga/alynx.html. |
| EMACS w3-mode | Multi-platform browser for EMACS editor. Runs under Gnu EMACS on the Amiga. FTP from ftp.cs.indiana.edu/pub/elisp/w3. | |
| MACINTOSH | Enhanced | From Spyglass. Multi-platform. |
| Mosaic | Commercial version of NCSA Mosaic. Can only be licensed by OEMs. Home page at http://www.spyglass.com. | |
| MacWeb | From EINet. FTP from ftp.einet.net/einet/mac/macweb. | |
| NCSA Mosaic | Multi-platform and still free (see fig. 2.9). FTP from ftp.ncsa.uiuc.edu/Mac/Mosaic. | |
| Netscape Navigator | Tables, HTML extensions. Free to nonprofit and educational institutions; free 90-day evaluation for individuals.Home page at http://home.netscape. com/info/index.html. FTP from ftp://ftp.netscape.com. | |
| MS/DOS | DOSLynx | Can view GIFs, but not in-line. FTP from ftp://ftp2.cc.ukans.edu/pub/WWW/DosLynx. |
| Minuet | Both text-mode and graphics-mode display. FTP from ftp://minuet.micro.umn.edu/pub/minuet/latest/minuarc.exe. | |
| NEXTSTEP | CERN WorldWideWeb | Out of date; editor not operational. Requires NeXTStep 3.0. FTP from ftp.w3.org/pub/www/src. |
| EMACS w3-mode Netsurfer | (See Amiga listing) FTP from ftp.thoughtport.com/pub/next/netsurfer. Home page at http://www.netsurfer.com. | |
| OmniWeb | Home page at http://www.omnigroup.com/. FTP from ftp.omnigroup.com/pub/software/. | |
| SpiderWoman | Multithreaded, graphical. FTP from sente.epfl.ch/pub/software. Home page at http://sente.epfl.ch/. | |
| TEXT-MODE UNIX/VMS | EMACS w3-mode Line Mode Browser Lynx PERLWWW | (See Amiga listing) For dumb terminals. FTP from www.w3.org/pub/www/src. For VT100. FTP from ftp2.cc.ukans.edu. By Tom Fine. TTY-based, written in PERL. FTP from archive.cis.ohiostate.edu/pub/w3browser /w3browser0.1.shar. |
| VMS | By Dudu Rashty. FTP from vms.huji.ac.il/www/www_client. | |
| VM/CMS | Albert | FTP from ftp.nerdc.ufl.edu/pub/vm/www/. |
| Charlotte | Written in REXX, runs on any CMS from v5 to v11. Gopher at gopher://p370.bcsc.gov.bc.ca. | |
| WINDOWS 3.1/NT/95 | Cello | From Cornell. Outdated. FTP from ftp.law.cornell.edu/pub/LII/cello. |
| CompuServe Mosaic EMACS w3-mode Emissary | From CompuServe. Comes with CompuServe subscription.(See Amiga listing) From Wollongong. Home page at http://www.twg.com. | |
| Enhanced Mosaic I-COMM | (See Macintosh listing) Operates without a TCP/IP connection.Requires UNIX or VMS shell account. Home page at http://www.best.com/~icomm/icomm.htm. | |
| Internet Explorer | From Microsoft (see fig. 2.10). Many HTML extensions. Home page at http://www.microsoft.com. | |
| WINDOWS 3.1/NT/95 | InternetWorks | Now a part of Global Network Navigator and America Online. For information, contact http://www.gnn.com. |
| Netscape Navigator NetShark | (See Macintosh listing) From InterCon Systems. Home page at http://netshark.inter.net. Supports HTML extensions. FTP Lite version from netshark.inter.net/pub/netshark/. | |
| Quarterdeck Mosiac | From Quarterdeck. HTML extensions. 30-day evaluation copy downloadable from http://www.qdeck.com/qdeck/demosoft/ Qmosaic. | |
| SlipKnot | Operates without SLIP or PPP connection. Requires UNIX shell account. FTP from oak.oakland.edu/SimTel/win3/internet. Home page at http://www.interport.net/ slipknot/slipknot.html. | |
| UdiWWW | Supports most of proposed HTML 3.0 plus Netscape extensions. Home page at http://www.uni-ulm.de/~richter/ udiwww/index.htm. | |
| WinMosaic | From NCSA. FTP from ftp.ncsa.uiuc.edu/PC/Windows/Mosaic. Home page at http://www.w3.org/hypertext/WWW/ MosaicForWindows/Status.html. | |
| WINDOWS 3.1/NT/95 | WinWeb | From EINet. FTP from ftp.einet.net/einet/pc/winweb/winweb.zip. |
| IBM OS/2 | WebExplorer | Multithreaded with visual map of session. FTP from ftp01.ny.us.ibm.net/pub/WebExplorer. |
| WebSurfer | From Netmanage. Included with Chameleon TCP/IP software package. | |
| X/DECWINDOWS | Arena | Test bed for HTML Level 3. FTP from ftp.w3.org/pub/www/arena. |
| Chimera | Uses Athena (doesn't require Motif). FTP from ftp.cs.unlv.edu/pub/chimera. | |
| EMACS w3-mode Enhanced Mosaic MMM | (See Amiga listing) (See Macintosh listing) Tcl/Tk user interface. Supports plug-in applets written in Caml Special Light. Home page at http://pauillac.inria.fr/~rouaix/mmm. | |
| NCSA Mosaic for VMS | (See Macintosh listing) | |
| NCSA Mosaic for X | (See Macintosh listing) | |
| Netscape Navigator | (See Macintosh listing) | |
| Quadralay Mosaic | From Quadralay. Commercial Mosaic for UNIX (Windows and Macintosh versions planned). Home page at http://www.quadralay.com/products/ products.html#gwhis. | |
| TkWWW | UNIX Browser/Editor for X11. Supports WSYIWYG HTML editing. Home page at http://www.w3.org/hypertext/WWW/ TkWWW/Status.html. | |
| Viola for X | Two versions: one using Motif, one using Xlib. HTML Level 3 forms and tables. FTP from ora.com/pub/www/viola. Home page at http://xcf.berkeley.edu/ht/projects/ viola/README. |
The information in this table came from the World Wide Web Frequently
Asked Questions (FAQ) list, which is maintained by Thomas Boutell.
You can download the latest version at http://www.boutell.com/faq/
or http://www.shu.edu/about/WWWFaq/.
| Note |
Batch-mode browsers retrieve the contents of a URL specified on the UNIX shell command line and are intended for use in scripts. (Most of the text-based UNIX browsers can also do this.) One is available at ftp.cc.utexas.edu/pub/zippy/url_get.tar.Z. Another, written in extended Tcl (tclX), is available at http://hplyot.obspm.fr/~dl/wwwtools.html. |