World Wide Web

The World Wide Web (WWW) is a part of the Internet that provides you with an interactive graphical interface, allowing you to view, manage and search through useful information. To reach the Web you must have a Web browser application, such as Internet Explorer, Netscape or Safari.

The Preferences windows in a browser lets you customise its operation. For example, increasing the size of a browser’s cache allows it to store more of your recently visited pages in RAM, making navigation quicker. Similarly, turning off the display of pictures, video and sound speeds things up, although this often makes pages difficult to view.

  Using a Web Browser

The following information applies to Internet Explorer, although other browsers are similar. You can visit a Web site in Explorer by typing the URL in the Address box, then pressing Return or clicking the button. Once a page appears you can click on a hyperlink to move to another location. These links usually appear as underlined text or as a graphical element.

Pages that appear in the Go menu are kept in the browser’s cache until it’s full, allowing you to have another look when you’re working offline. You can click on the Back and Forward buttons (or press -⇠ or -⇢) to navigate through the pages or you can hold the mouse down over these buttons to see a list of recently viewed pages.

Navigation inside a page is easy: you can press -⇡ or Home to move to the top or press -⇣ or End to reach the bottom. And the Tab key moves you through the links, although this can be changed under Preferences ➡ Browser Display.

The Button Bar

This bar, which appears along the top of all windows in Explorer, is enabled whenever a check mark is present alongside Button Bar in the View menu. You can change the buttons by selecting View ➡ Customize Toolbars.

The following buttons are particularly useful:-

ButtonEffect
BackMoves you back to a previously visited page
ForwardMoves you forward to the next page previously visited
StopStops the next page from downloading
Refresh Reloads the current page; useful if something goes wrong
HomeVisits a chosen home page, as selected under Preferences
SearchVisits a chosen search page, as selected under Preferences
Mail Switches you into a chosen e-mail application
FavoritesOpen the Favorites list
Larger Increase the font size displayed in the page
SmallerReduces the font size displayed in the page
Preferences Opens the Preferences dialogue for customising settings

Tabs

Explorer provides several tabs along the left-hand edge of its main window. The Search tab lets see the results of a search as you work through the items while the Favorites and History tabs let you keep track of any interesting sites.

Fonts

If you don’t like the font size of the current page, select View ➡ Text Zoom and choose a different scaling. Alternatively, click Larger or Smaller in the button bar or press -+ (plus) or -- (minus) to nudge the size up or down.

The font and style of a Web page is normally set its designer. If the fonts aren’t specified, the browser uses those chosen under Language/Fonts in the Web Browser section of the preferences. The Size is normally be set to 12, giving a 12-point font , while Resolution is usually at 96 dpi (default), which makes the browser behave as on a Windows computer.

You can make Explorer use selected fonts instead of those in pages by choosing Web Content from the Web Browser section of the preferences and deselecting Allow page to specify fonts, although this can mess up the look of some pages.

Local Browsing

If you type /// into the Address box and click the button you’ll see a list of items, including your own computer. To navigate through the files, click on the name of your disk drive. You can then open items in the same way as you would in the Finder. Furthermore, you can copy items onto the desktop by simply dragging them across the screen.

  Plug-Ins

A plug-in is a mechanism, sometimes with applications or other files, that lets you view or listen to material that your browser can’t normally accommodate, such as movies or special sounds. You can install a plug-in for the Classic Mac OS by quitting the browser and dragging the necessary items into the Internet Plug-Ins folder, inside the System Folder.

In most instances, a new plug-in is activated when the browser is restarted. However, in Internet Explorer you can also activate a plug-in by opening File Helpers in the Receiving Files section of the preferences. You must then locate the kind of file to process, either by its Description or by filename Extension, and then click on Change. This reveals an Edit File Helper window that shows how the particular kind of file should be processed. In the Handling pane you should ensure that How to handle is set to View with Plug-in and that the Plug-in name is set to the correct name.

MIME Types and Extensions

Files on the Internet are identified by detecting the document’s MIME type or by reading its filename extension, although the latter isn’t always reliable. Each plug-in accepts one or more MIME types, each of which is related to one or more corresponding filename extensions.

A wide range of plug-ins are available. Some of those available for the Classic Mac OS are shown below, complete with the supported MIME types and related filename extensions.

AboutPeople

This special plug-in, provided with some versions of Now Contact, lets you read a contact’s virtual business card, also known as a vCard file. This can be used to store a person’s name, addresses, phone numbers, e-mail addresses, URLs, time zone, photograph and an audio clip, the latter normally used to assist in the pronunciation of the name.

application/vCard.vcf
text/x-versit.vcf

AboutTime

This is supplied with some versions of Now Up-to-Date, allowing you to look at the dates of events.

text/x-nowevent.vef

This is similar, but not identical, to a virtual calender or vCal file, which can store events of a specific length or to-do items that can be assigned to a particular person.

Beatnik

This free plug-in from Headspace lets you play Rich Music Format (RMF) files. These are similar to a Standard MIDI File (SMF), although larger and less common, and can also be played from within the Beatnik Editor application. Instead of using QuickTime Musical Instruments, this plug-in employs its own synthesiser, which contains 32 voices, as well as 49 short sounds known as groovoids.

audio/rmf.rmf
audio/x-rmf.rmf

Default Plugin or Default Plug-in

This is the standard plug-in supplied with your browser, which enables it to read HTML files and other normal Web documents. Note that the file used by Explorer has the name Default Plugin, whilst that used by Netscape is called Default Plug-in, allowing both files to co-exist in the same folder, if necessary. You shouldn’t remove either of these plug-ins.

e-Vue image Viewer

This plug-in is used for viewing real-time video images that are encoded using the MPEG-4 system.

image/x-mpeg4-vtc.vtc

Macromedia Products

Macromedia produce several plug-ins, together with supporting documents and files, for ShockWave and other file formats. The full names of the following plug-ins aren’t given, as they vary according to whether the version is intended for use with a 680x0 or PowerPC-based computer.

AW-Shockwave

Lets you to read AuthorWare files. When you open a file, a security dialogue usually appears, although this can be prevented if you flag the site as ‘trusted’ and tell the plug-in to omit the dialogue for all such sites. If you choose not to trust a location, the file opens but may not work properly.

application/x-authorware-map.aam .aas

Dir-Shockwave

Lets you play Director documents, which can contain movies and other interactive material.

application/x-director.dcr .dir .dxr

FH-Shockwave

Lets you view older FreeHand graphics documents, allowing you to zoom and pan, either by means of the keyboard or by employing an optional toolbar above or below the image.

image/x-freehand.fhc .fh4 .fh5

Shockwave Flash

Lets you view Flash interactive files, including older documents designed for Futuresplash Player. This is a binary format, which means that it uses smaller files than a text-based document.

application/x-shockwave-flash.swf
application/futuresplash.spl

MidiPlug

Although the QuickTime Plugin file provides excellent support for MIDI files you can use this Yamaha plug-in as an alternative. It comes complete with built-in musical instruments that can replace those provided by QuickTime Musical Instruments.

audio/mid.kar .mid .midi .smf
audio/midi.kar .mid .midi .smf
audio/x-midi.kar .mid .midi .smf

PDFViewer

Lets you read Acrobat PDF files from within your browser. It also presents you with the navigation buttons and other toolbar items that normally appear in Adobe Reader or Acrobat Reader (Adobe).

application/pdf.pdf

QuickTime Plugin

This lets you hear and view QuickTime and other material from within your browser, but only if the appropriate QuickTime software is present on your machine. The plug-in plays movies containing various material, including MIDI musical sequences and text. Its fast-start feature presents the first frame of a movie almost instantly and begins playback even before downloading is complete. The plug-in also lets you navigate around QuickTime VR panoramas and objects.

Any movie used on the Web must be flattened, a process that combines the document’s resource and data forks into a single file. To do this you must register yourself for QuickTime Pro and then open the movie in QuickTime Player. Now select File ➡ Save As, ensuring that you activate the boxes marked Make movie self-contained and Playable on non-Apple computers.

The following table shows just a few of the MIME types supported by this plug-in.

audio/basic.au
audio/x-aiff.aif
audio/x-wav.wve
video/mpeg.m1v
video/quicktime.moov .mov .qt
video/x-msvideo.avi

RealSpace Plugin

This lets you view images created using Virtual Reality Markup Language (VRML) version 2.0.

model/vrml.ivr .wri
i-world/ivrml.ivr

SVG Plugin

For viewing Scalable Vector Graphics (SVG) images, a plain-text format that can include XML metadata to describe its content. This kind of file can also use XML for rollover effects.

image/svg.svg .svgz
image/svg-xml.svg .svgz

Vivo Plugin

For viewing Vivo audio and video material.

video/vivo.viv
video/vnd.vivo.viv

Security on the Web

Any Internet connection poses a risk to the data on your computer. It can also threaten your finances should someone discover your credit card number following online shopping. To ensure that your information is kept private you must only use secure Web sites for financial transactions, avoiding any sites of a dubious nature.

The Secure Sockets Layer (SSL) mechanism is often used to scramble credit card details, although some sites employ the Secure Electronic Transaction (SET) system, in which the credit card number isn’t actually given to the retailer: instead the number is checked by the card scheme and the trader is then informed if the card is valid and has sufficient funds.

Encryption

Most modern browsers support RSA encryption using 40, 56 or 128-bit coding, as well as the more recent Transport Layer Security (TLS) form of encryption. Until recently, 128-bit RSA encryption couldn’t be built into any browser software that was exported outside of the USA, although for most purposes the 40 or 56-bit systems are perfectly adequate. However, where higher levels of safety are required at a secure site, as in electronic banking, the server can temporarily upgrade any browser for 128-bit encryption by sending it a Global Server Certificate.

Unfortunately, getting a certificate uses time on the Internet. One alternative to this is Fortify, a special application that patches a ‘weak’ version of Netscape Navigator, enabling it to work properly with 128-bit encryption. Since Fortify doesn’t actually contain any 128-bit encryption software it doesn’t infringe the restrictions that once applied to such material. However, now that 128-bit encryption is available worldwide, most users won’t need to use to such an application.

Retained Data

Most browsers store some of the material that you’ve viewed on the Web, employing the following mechanisms:-

History

This consists of a list of the addresses of the sites you’ve recently visited, which although useful, allows anyone else with access to your computer to know where you’ve been. The Classic Mac OS version of Explorer keeps this in a file called History.html, in the Explorer folder inside Preferences, which is in the System Folder.

Cache

The content of recently viewed pages is held in a cache, which in the Classic Mac OS version of Explorer is kept in a file called IE Cache.waf, inside a folder called MS Internet Cache inside Preferences.

Download Cache

Recently downloaded data is kept in a Download Cache file, which in the Classic Mac OS version of Explorer is in the Explorer folder, as mentioned above. Files that have been processed via a plug-in or other applications may be found in the Temporary Files folder, also in the Explorer folder.

To stop Explorer’s download cache you must select Download Options in the Receiving Files section of the preferences. Under Download Manager Options you should choose Immediately remove items after they have been downloaded.

Other Risks

The following should be considered when browsing the Web or creating a site:-

Cookies

Web users often worry about cookies, small text files sent by a Web server, kept on your computer and then used by the server when you next visit a site. The information they contain can be used to modify subsequent presentation of the site’s pages or to keep a record of sites that you’ve visited.

Cookies can also contain information about your computer, Internet address and browser. This might seem quite insignificant but it’s actually quite easy to convert your numerical Internet address, also known as an IP address, into a real address. It’s worth noting, for example, that the Interarchy (Anarchie) application has a Lookup Domain feature designed for this purpose. Fortunately, if you have a dial-up connection your IP address changes each time you connect to the Internet.

Rather worse, a cookie can also be used to store passwords or security codes, although the information in each cookie is only normally sent back to its originating Web server, which isn’t a real problem. However, some sites allow other organisations, often known as a profiler company, to extract information about the sites that you’ve visited. On rare occasions, key information within cookies has been linked to a database that contains real names and addresses.

Fortunately, most modern browsers let you disable the operation of cookies, although this may result in persistent beeps and dialogues appearing whenever a cookie is requested. Happily, this doesn’t usually occur in Internet Explorer.

If you don’t want to turn off cookies entirely you may be able to opt out of cookie operation at sites that allow you to do this, although this requires special software. Alternatively, you could use a third-party application such as MacWasher, NoCookie or MagicCookie Monster.

User Agent Identification

Many Web sites use JavaScript to identify the type of browser that you’re using or your computer platform. These details, known as the user agent, allow the current site to feed you slightly different pages, based on the vagaries of your software or the site’s marketing objectives. Although not a serious security risk, this also allows sites to block users that employ a particular browser or platform. In particular, this mechanism is sometimes used against would-be Mac OS customers.

Fortunately, some browsers incorporate features that can be used to fool any site that you visit that you’re really using an entirely different browser or platform. To do this in Apple’s Safari application in Mac OS X you must first enable its Debug menu, which you can do by opening the Terminal application and typing the following:-

defaults write com.apple.Safari IncludeDebugMenu 1

Having relaunched the application, you should discover the new menu. This has a User Agent submenu, which lets you pretend to be one of several browsers, including Windows MSIE 6.0, which is Internet Explorer 6.0 on the Windows system. This may bring to life those things that didn’t work before and enables you to import bookmarks for any of the listed browsers.

E-mail Address Security

Many people include their e-mail address on a website. Unfortunately, special applications known as spam harvesting spiders regularly ‘trawl’ the Web in the search of valid addresses. Such trawlers can be beaten by omitting the e-mail address from your own site, or by disguising it so that can’t be detected. The simplest method is to replace the address by a graphic: this means that your customers have to use their e-mail application manually, although this isn’t a huge hardship.

Better still, if you run your own e-mail and Web servers, you can use a CGI script that allows visitors to submit to your site, but without letting them know your e-mail address. However, you must also ensure that the address isn’t hidden away in the HTML ‘code’ that makes up your pages.

There are other ways of hiding an address, either manually or by using software such as Spam Stopper or Spam Vaccine. The simplest method is replace the normal characters in the address by the equivalent numerical entities, such as 0 to 9 for digits 0 to 9, A to Z for uppercase letters A to Z and a to z for lowercase letters a to z.

Better still, the address can be broken up using the standard JavaScript document.write command, as shown below, although this only generates the e-mail address when JavaScript is enabled:-

<script type="text/javascript">

<!--

document.write('<a href="mailto:'+'mail&#64;'

    +'bloggs'+'.org.uk?subject=Web Page Enquiry">'+'Bloggs</a>');

// -->

</script>

You can confuse the spiders even more by using entities for all or part of this information: in this example the @ character has been coded to make the information look less like an e-mail address.

©Ray White 2004.