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Mosaic

1. History
1. The first graphical Web browser: originated about 1992 or 1993
2. Developed at the National Center for Supercomputing Architecture (NCSA)in Illinois
3. Became the fastest-growing software of 1993-4
2. Major Variants
1. Several variants were used
2. Mosaic is largely relegated to history now
3. In Comparison...
1. Mosaic lacks many formatting and security features available on newer browsers- including the ability to handle "frames" and many types of multimedia now popular on the Web
2. Divergent standards plague the Web, as each group adds new features before the standards are agreed on.

Mozilla

1. History
1. Founded by people who had worked at NCSA
2. Name derived from "Mosaic" + "Godzilla"?
3. Originally made available under the name Netscape Navigator
4. Incorporated several popular new features
5. By late 1995, Netscape was incorporated and had become one of the fastest-ever growth stocks on the New York Stock Exchange
2. Major Variants
1. Netscape Navigator is available for Windows, Macintosh, several versions of Unix, and other computers
2. Mozilla is available under its own name, using a unique license that encourages developers to build their own Web browsers based on its basic browser "engine". Firefox is a browser built by the Mozilla organization using their own "engine"; Netscape Navigator is built by a separate but related organization, also using the Mozilla 'engine".
3. In Comparison...
1. Mozilla/Netscape has fallen far behind Microsoft's Internet Explorer (MSIE) in popularity since 1998.
2. However, its capabilities are pretty much on a par with MSIE.
3. The Mozilla Foundation is a non-profit organization, and its active encouragement of the free use of the Mozilla browser "engine" may well lead to growth in its popularity.
4. For more information...visit:
   1. Mozilla site at http://www.mozilla.org/
   2. Netscape's site at http://home.netscape.com

Microsoft Internet Explorer

1. History
1. Officially introduced in mid 1995, with Windows 95
2. With the backing of software giant Microsoft, Explorer has grown rapidly
3. As of late 1997, it is the second most popular Web browser, after Netscape
2. Major Variants
1. Internet Explorer is available for Windows 95, Windows NT, Windows 3.1,and Macintosh.
2. The current version is available for free downloading from Microsoft's Web site. Check the MS Web site at http://www.microsoft.com/windows/ie/default.htm to find the latest version.
3. Macintosh versions are often quite different from Windows versions (even with the same version numbers) in appearance and in how they render HTML code.
3. In Comparison
1. Given the financial power and development experience of Microsoft, it is no surprise that IE is a strong contender for "most popular Web browser".The Department of Justice has brought Microsoft to court on anti-trust(monopoly) charges (October 1998) partly because of Microsoft's inclusion of its Web browser in Windows 95 and 98. For details, visit the Department of Justice Web site at http://www.usdoj.gov/atr/cases/ms_index.htm,and read Microsoft's side at their site, http://www.microsoft.com/presspass/legalnews.asp
2. IE has almost all the features of the most advanced version of Netscape,and has added many new, non-standard features of its own. This has fueled an ongoing "browser war" between Microsoft and Netscape for dominance in this high-profile market.

Opera

1. History
1. Developed in 1994 by Jon S. von Tetzchner and Geir Ivarsøy while working for Norwegian telecom Telenor.
2. Received recognition beginning in 1997 for small size, high speed, and compliance with W3C standards
2. Major Variants
1. Opera is available on many computers, including Windows, Macintosh, Linux,BeOS, and EPOC.
2. Versions run on several hand-held wireless devices, including Internet cell phones and palmtop organizers
3. In Comparison
1. Opera prides itself on its small, fast code
2. Opera supports all common Web standards needed to surf the web, including markup languages (HTML and XML), network and security protocols (HTTP, SSL and TLS), style sheets (CSS1 & CSS2) and programming languages (ECMAScript/Javascript and DOM).
3. For more information, visit http://www.opera.com/index.html

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Other Browsers

• Non-graphical browser: Lynx. For more info, see E. Stephen Mack's page, http://www.emf.net/~estephen/goodlynx.html
• Advanced browsers: Browsers and add-ons for Virtual Reality Modeling Language (VRML) are also available. Other sources of information are available through Yahoo!s browser section, http://dir.yahoo.com/Computers_and_Internet/Internet/World_Wide_Web/Virtual_Reality_Modeling_Language__VRML_/Browsers/

For more information...

• Wikipedia has an informative entry on browsers, including history and background details (http://en.wikipedia.org/wiki/Web_browser)
• Yahoo! has a section listing many browsers, with links to sites for further information (http://www.yahoo.com/Computers_and_Internet/Software/Internet/World_Wide_Web/Browsers/)
• For a complete list of Macintosh browsers, with reviews, see Darrel Knutson's page (http://darrel.knutson.com/mac/www/browsers.html)
  

Who's on Top?

Browser usage is recorded by most Web servers, but most don't make them available publicly. Usage varies by site, by country, and by region. One publicly available site log is displayed by the institution that originated the graphical Web browser, the University of Illinois at Champaign/Urbana. Get their latest figures at http://www.cen.uiuc.edu/bstats/latest.html

A compilation of statistics is available from W3Schools (marred only by the obnoxious nature of their advertising): http://www.w3schools.com/browsers/browsers_stats.asp

Files and Locations

If you don't have a network or modem attached to your computer, you can still use a Web browser locally, as long as the network software is available. This network software was often called a "stack", because it implemented several layers of the OSI model. 

OSI Model View

The Stack and the Operating System

• The Browser handles the upper layer tasks (7 and 6; possibly 5)
• The Operating System (Windows, Mac OS, Unix...) handles the middle layers (2-4 or 2-5)
• The Physical Layer (1) is handled by a variety of devices and their associated software, depending on how your computer is connected to the Internet

During those years, connecting to the Internet with a Web browser or email client was much more of a challenge than it is now. It was necessary to install not only a browser, but also software to handle the middle layers of the OSI model. Several third-party solutions were available, either free or at reasonable prices. These were known as "stack" programs. Here are some examples of stack programs that were widely used:

• Trumpet Winsock (shareware)
• Spry Internet Dialer (came with Internet in a Box) and CompuServe Internet Dialer (came with a subscription to CompuServe)
• Chameleon for Windows 3.1 included a stack (shareware)

Processing Files

1. Figure out where the file is located. If it is a local file, the browser can skip a couple of steps. If it is a site on the Internet, it needs to find the actual IP (numeric) address. This involves asking the Domain Name Server (DNS). The DNS is a computer with a database of names - very much like a phone book. It may be your local host computer, or some regional server such as Merit's MichNet DNS server. (See module NG04c.) If the DNS server does not respond, or the name isn't in its list, you get an error message and the process stops dead.
2. Contact the remote Web server host (if the file requested is not on the local computer). A TCP packet is made up and sent through layers 3, 2, and 1 requesting to set up a session on the Web port (usually 80).
3. If the host responds that it is able to create a session on the desired port (layer 5), the browser sends an HTTP request (layer 6) to ask for the file you want. Assuming the file is really there, the Web server (layer 7 on the remote computer) sends the file. The browser will try to give you a progress report in the lower window border. (If the file you want is not there, you get an error message.)
4. Processing HTML (Hypertext Markup Language - layer 7) is the next step for the browser. This happens for both local and remote files. The browser identifies HTML tags and interprets them, putting in the different sizes and styles of fonts, the spacing between lines, creates tables, and does all other formatting. To see the HTML code for this file, use the menu View...Source. The browser lines up the text according to the width of the browser's window.
5. Getting secondary files is usually necessary. These secondary files are listed in the HTML code, often with instructions on how to handle them. Most commonly, the secondary files are graphic images placed "inline" - that is, they are to appear as part of the page. Most browsers are set up to handle .gif, .jpg, and .png images, so pictures in other formats can't be included within a Web page.
• GIF: CompuServe's Graphic Interchange Format is useful because it is designed for use on all computers, and it is stored in a compressed way, which makes transmission of the image relatively fast.GIF is especially useful for charts, diagrams, and other images that contain lines, texts, and large areas of the same color. It can show only 256 colors.
• JPEG: the Joint Photographic Experts' Group has defined another compressed graphic image format which can be shared between computers rapidly. (These are not as commonly used as GIF images,but are growing in popularity.) JPEG was intended for use mainly with photographs,and can show up to 16 million colors.
• PNG: Portable Network Graphics was designed to have the advantages of both GIF and JPEG formats. It is relatively complex, and is used infrequently because its complexity, and because PNG formatted pictures tend to be somewhat bigger than the same pictures formatted with JPEG or GIF.
• Other files of many types can be handled separately (that is, not on the Web page itself) if you have set up your browser to provide a plug-in or helper application (discussed in module W06c). Helper applications open their own windows to show the special material.
6. Closing the connection: When the browser has requested all the secondary images in the HTML text, it sends a packet advising the remote Web host (assuming you're using one) that it is closing its Session Layer (5) port80. This way, the host is free to process other requests while you read your Web page. Many Web browsers have animated icons in the upper right section of the screen. When the Session Layer connection with the host is open, these show some kind of movement; when the connection is closed, the movement stops.

Like any software, Web browsers have many options you can set. These can affect many aspects of your browser experience, including what happens when you start the program, how the toolbars look, what font and color the screen shows, and also the performance of the browser when it interacts with the Web. We'll hit the high spots here. You may want to try some of these; others I recommend you leave alone - you don't want too many unpleasant surprises! (Module W11h is an exercise that takes you through experiments with many of these options.)

Where to find your Options

Each browser has a slightly different location for options in its menu system. This table shows you where to find them:

In the following sections, we'll look at what options to set for your browser's ...

• Appearance
• Starting Place
• Helpers
• Security

Appearance

Browsers offer many options for affecting appearance, including toolbars, bookmarks, "skins", colors and fonts of pages. For the most part, you can do whatever pleases you with appearance, but here is some advice about colors and fonts ...

Colors

Generally, leave the colors alone. Few Web pages are created without thought for their color combinations, and they usually work well. The exceptions would be (1) if you have a visual impairment, or (2) if you come across a page whose colors are so poorly designed you can hardly read it. In either case, experiment with what works best in your case.

Fonts

The default fonts in all browsers are:

• Overall default: Times New Roman
• Sans-serif default: Arial
• Monospace default: Courier New

Each of these works reasonably well, and Courier New is excellent (for what it is). However, there are better choices for the overall and (to some extent) sans-serif defaults. I recommend the following fonts which were developed specifically for on-screen computer viewing:

• Overall default: Georgia
• Sans-serif default: Verdana

Starting Place

The "Home" or starting-place for your browser is generally set by the browser developers to further their commercial ambitions - in other words, they start, by default, at their parent company's home page. Many Internet service providers (ISPs) follow this lead when they provide you with a browser, and set it to point to their own home or portal page.

However, you are free to set your browser's "home" page to anything you like; I highly recommend it! If you enjoy making Web pages, create a page the suit your taste and has links to what you find most interesting or useful. I've found it very helpful to my own productivity, because I've arranged my home page with that in mind. (Take a look if you like.) My home page lives on my laptop, as well as on my Web site, so I can use it when I'm off-line.

Helpers

Helper applications and plugins are used by browsers to handle files they weren't designed to work with. Some of the best-known include:

• Adobe Acrobat PDF files
• Music
• Videos

... and there are many more. For the most part, you don't have to concern yourself about these, because your operating system will inform the browser what helper applications to use for most file types. Plugins work as part of the browser, and usually have to be downloaded separately for each brand of browser you use. Fortunately, most plugins load themselves without much effort on your part.

You may want to set the applications in the browser's options if the operating system's default is not to your liking. Of course, you can also change the OS default, but perhaps there's a reason to keep the OS default one way and the browser's default another.

For more information on helper applications and plugins, see module W06c.

Browser Security

Several aspects of security, privacy, and freedom from annoyance affect the browser; the most apparent are ...

• History
• Security Certificates and SSL
• Cookies
• Pop-up windows

History

The "History" consists of two parts: a list of addresses your browser has visited, and the associated cache of files. It is useful for two purposes:

1. To find your way back to an address you've been to, but don't recall.
2. To speed your browser's performance, it saves the files you've viewed in a folder on your hard drive. This is its cache. When you want to revisit any page you've been to recently, the browser checks to see if it has the page in cache. If so, it checks to see if the version on the Web is newer, and if not simply shows you the cached version without waiting to download another copy of the same thing.

Generally, history is a good thing to have around. There are a couple of situations where it might not be so good:

• When you've visited a Web site you'd rather nobody knew about. ;-)
• When your disk gets too full, and you need to make space.

Using the browser's options, you can set the length of time the cache keeps files around, you can also set the maximum size of cache, and you can have the cache emptied immediately. Ordinarily, the default of 9 days' history is adequate but not excessive.

Security Certificates and SSL

The Internet was designed with the assumption that we could trust everybody who uses it. That may have been true when it was limited to research scientists, but clearly, that's not the case now. There are many documented cases of sensitive information falling into unfriendly hands while traveling through Internet switches and routers owned by unscrupulous operators.

In order to keep information private, and to insure it's not tampered with while it's on the way, a security protocol known as Secure Sockets Layer (SSL) was developed. (This protocol operates in the OSI region between layers 4 [Transport] and 6 [Presentation].) The newest version of SSL (as of late 2004) is known as SSL 3.1 or Transport-Layer Security (TLS).

Audience:

Objectives

1. Discuss the advantages and disadvantages of the major web browsers
2. Discuss browser compatibility issues
3. Describe what Web browsers do, in general, when they find and display information,including:
1. Contacting the server
2. Formatting text
3. Dealing with images
4. Dealing with other non-HTML files using built-in browser features and "plug-ins"
4. Describe "plug-in"
5. Explain the ways in which you can retrace your steps to find sites previously visited
6. Discuss the concept of caching files
7. Explain the difference between opening a "file" and opening a "location"
8. Describe printing and printing options
9. Explain how to save network objects on your disk:
1. documents
2. graphics
10. Cut-and-paste information from a browser:
1. URLs
2. Text elements
11. Use the document search feature in a browser
12. Reload or Refresh a document
13. Use the Backward, Forward, and Home buttons or navigation (Go) menu
14. Use bookmarks or hot links and save the file
15. Discuss the major options and preferences

Module W10c: World Wide Web Browser Details

Click here for review questions.

Author:

Laurence J. Krieg

Institution:

Department of Computer Information Systems, Washtenaw Community College

Date:

Original December, 1995

This version  Monday, 31-Aug-2009 11:48:00 EDT