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ALT. Alternative HTML tag that takes the place of graphics on text-only browsers.

ASCII. American Standard Code for Information Interchange; a standard code for representing characters as binary numbers, used on most computers and terminals. ASCII is often called "plain text," in contrast to formatted text, which makes use of special characters (curly quotes, etc.), formatting commands (bold, italic, etc.), or proportional fonts (Times, Helvetica, etc.).

bandwidth. Network transmission speed. The greater the bandwidth, the more information can be transferred at a time.

banner graphic. A graphic at the top of a Web page that uniquely identifies a document. Banner graphics often incorporate organizational logos.

bit depth. The number of data storage bits available to describe each sample point of a bitmapped image. Most current color or grayscale monitors display 256 colors or shades, or 8-bit color.

browser. A Web client application that allows the user to navigate the information databases of the World Wide Web. There are browsers for systems with graphical user interfaces and for text-based systems.

CGI. Common Gateway Interface; executable scripts stored on a server that are necessary for such dynamic functionality as interactive forms and image maps.

client. A software application that accesses a service from a server somewhere on the network. A client is usually on your local desktop computer or on a host that you access via Telnet.

Ethernet. A protocol for interconnecting computers and peripheral devices at high speed, currently up to ten million bits per second. Ethernet-connected computers are directly connected to the Internet.

extensions (Netscape). HTML tags that allow extended functionality such as centering, tables, backgrounds, and font size manipulation. Netscape extensions are not presently supported by other browsers.

external image. Image that is not contained within a Web page. A link for an external image has to be activated before that image can be downloaded.

GIF. Graphic Interchange Format; a graphics compression format used to transfer images over the Internet. GIF format is more commonly used for inline images.

graphical browser. A Web client, such as Netscape or Mosaic, that can display graphics saved in GIF or JPEG format.

grid. An imaginary structure of horizontal and vertical lines that organizes pages into consistent zones into which text and graphics can be fit. An underlying grid structure can be helpful in designing pages for the Web.

home page. The first or main document in a Web site.

HTML. HyperText Markup Language; the collection of styles and markup tags used to define the components of a World Wide Web document.

image map. Several links imbedded within a single graphic. Image maps, also referred to as clickable maps, require CGI scripts to work.

inline image. Image contained within a Web page that is automatically loaded when the page is loaded.

interlaced image. An image that loads on a graphical browser in horizontal bands, each of which repaints at successively higher resolutions (has a "Venetian blind" effect).

Internet. The worldwide "network of networks" connected to each other using IP and similar protocols.

IP. Internet Protocol; the most important Internet protocol. IP allows information to traverse multiple networks.

JPEG. Joint Photographic Experts Group format; a graphics compression format used to transfer images over the Internet. JPEG offers more efficient compression for continuous tone (photo-like) images than GIF.

Netscape. The supported World Wide Web browser at Penn, developed by Netscape Communications Corporation.

PDF. Portable Document Format; an electronic format developed by Adobe Systems Inc. that retains the fonts and layout of a hard-copy document, independent of computer platform.

PPP. Point-to-Point Protocol; the successor to SLIP. PPP can be used to connect to the Internet with a standard telephone line and a high-speed modem.

server. A networked computer that contains public resources or services that can be accessed using software applications called "clients."

SLIP. Serial Line IP; a protocol that allows a computer to connect to the Internet with a standard telephone line and a high-speed modem.

text-only browser. A Web client, such as Lynx, that cannot display graphics.

transparent image. An image with an opaque background that looks like it "floats" on the background of a Web page. To create an image with a transparent background, you need a tool to convert the image to GIF 89a format. Then you can select one color of the GIF image (e.g., the background if it is one color) and define it as transparent.

World Wide Web. A hypermedia-based system for finding and accessing millions of documents on thousands of different computer hosts on the Internet. Also known as WWW or Web.

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