Internet Languages

ASP

What is ASP?. An ASP (Active Server Page) is an HTML page that includes one or more scripts (small embedded programs) that are processed on a Microsoft Web server before the page is sent to the user. An ASP is somewhat similar to a server-side include or a Common Gateway Interface (CGI) application in that all involve programs that run on the server, usually tailoring a page for the user. Typically, the script in the Web page at the server uses input received as the result of the user's request for the page to access data from a database and then build or customize the page "on the fly" before sending it to the requestor. ASP is a feature of the Microsoft Internet Information Server, but, since the server-side script is just building a regular HTML page, it can be delivered to almost any browser. You can create an ASP file by including a script written in VBScript or JScript in an HTML file and then renaming it with the ".asp" file suffix. Microsoft recommends the use of the server-side ASP rather than a client-side script, where there is actually a choice, because the server-side script will result in an easily displayable HTML page. Client-side scripts (for example, with JavaScript) may not work as intended on older browsers.

Microsoft's Client and Server Scripting in Web Pages

C

What is C?. C is a structured, procedural programming language that has been widely used both for operating systems and applications and that has had a wide following in the academic and the business community. Many versions of Unix-based operating systems are written in C. C has been standardized as part of the Portable Operating System Interface (POSIX). With the increasing popularity of object-oriented programming, C is being rapidly replaced as "the" programming language by C++, a superset of the C language that uses an entirely different set of programming concepts, and by Java, a language similar to but simpler than C++, that was designed for use in distributed networks.

C++

What is C++?. C++ is an object-oriented programming language that is now generally viewed as the best language for creating mid-scale to large-scale application programs. C++ is a superset of the C language. A related programming language, Java, is based on C++ but optimized for the distribution of program objects in a network such as the Internet. It is somewhat simpler than C++ and has characteristics that give it other advantages over C++. However, C++ requires no "Runtimes" which are required by most other languages (such as Java) and, because of it's roots in C, is regarded as "the fastest" programming language.

MIT's Introduction to Object-Oriented Programming Using C++.

DHTML

What is DHTML? Dynamic HTML is a collective term for a combination of new Hypertext Markup Language (HTML) tags and options, style sheets, and programming that will let you create Web pages more animated and more responsive to user interaction than previous versions of HTML. Much of dynamic HTML is specified in HTML 4.0. Simple examples of dynamic HTML pages would include (1) having the color of a text heading change when a user passes a mouse over it or (2) allowing a user to "drag and drop" an image to another place on a Web page. Dynamic HTML can allow Web documents to look and act like desktop applications or multimedia productions. The features that constitute dynamic HTML are included in Netscape Communications' latest Web browser, Navigator 4.0 (part of Netscape's Communicator suite), and by Microsoft's browser, Internet Explorer 4.0. While HTML 4.0 is supported by both Netscape and Microsoft browsers, some additional capabilities are supported by only one of the browsers. The biggest obstacle to the use of dynamic HTML is that, since many users are still using older browsers, a Web site must create two versions of each site and serve the pages appropriate to each user's browser version. Both Netscape and Microsoft support: An object-oriented view of a Web page and its elements, Cascading style sheets and the layering of content, Programming that can address all or most page elements, Dynamic fonts. Each page element (division or section, heading, paragraph, image, list, and so forth) is viewed as an "object." (Microsoft calls this the "Dynamic HTML Object Model." Netscape calls it the "HTML Object Model." W3C calls it the "Document Object Model.") For example, each heading on a page can be named, given attributes of text style and color, and addressed by name in a small progam or "script" included on the page. This heading or any other element on the page can be changed as the result of a specified event such a mouse passing over or being clicked or a time elapsing. Or an image can be moved from one place to another by "dragging and dropping" the image object with the mouse. (These event possibilities can be viewed as the reaction capabilities of the element or object.) Any change takes place immediately (since all variations of all elements or objects have been sent as part of the same page from the Web server that sent the page). Thus, variations can be thought of as different properties of the object. Not only can element variations change text wording or color, but everything contained within a heading object can be replaced with new content that includes different or additional HTML as well as different text. Microsoft calls this the "Text Range technology." A style sheet describes the default style characteristics (including the page layout and font type style and size for text elements such as headings and body text) of a document or a portion of a document. For Web pages, a style sheet also describes the default background color or image, hypertext link colors, and possibly the content of page. Style sheets help ensure consistency across all or a group of pages in a document or a Web site. Dynamic HTML includes the capability to specify style sheets in a "cascading" fashion (that is, linking to or specifying different style sheets or style statements with predefined levels of precedence within the same or a set of related pages). As the result of user interaction, a new style sheet can be made applicable and result in a change of appearance of the Web page. You can have multiple layers of style sheet within a page, a style sheet within a style sheet within a style sheet. A new style sheet may only vary one element from the style sheet above it. Layering is the use of alternate style sheets or other approaches to vary the content of a page by providing content layers that can overlay (and replace or superimpose on) existing content sections. Layers can be programmed to appear as part of a timed presentation or as the result of user interaction. In Internet Explorer 4.0, Microsoft implements layers through style sheets. Netscape supports the style sheet approach but also offers a new HTML <LAYER>...</LAYER> tag set (that Microsoft does not support). Both approaches are being considered by the W3C Working Committee and both companies say they will support whatever W3C decides will be the recommended approach. Although JavaScript, Java applets, and ActiveX controls were present in previous levels of Web pages, dynamic HTML implies an increased amount of programming in Web pages since more elements of a page can be addressed by a program. Netscape includes dynamic fonts as part of dynamic HTML. This feature of Netscape's Navigator browser in its Communicator suite lets Web page designers include font files containing specific font styles, sizes, and colors as part of a Web page and to have the fonts downloaded with the page. That is, the font choice no longer is dependent on what the browser provides. There is no single specification for "dynamic HTML" since it's really a combination of several things. Netscape and Microsoft each have their own definitions and explanations of it on their respective Web sites.

Netscape's Dynamic HTML Developer Central W3 HTML 4.0 Specification and Style Sheets and the Document Object Model Project Cool' daily newsletter CNET's Dynamic HTML: A Web Revolution

HTML

What is HTML? HTML (Hypertext Markup Language) is the set of "markup" symbols or codes inserted in a file intended for display on a World Wide Web Browser. The markup tells the Web browser how to display a Web page's words and images for the user. HTML is defined in practice both by Netscape and Microsoft as they add changes to their Web browsers and more officially for the industry by the World Wide Web Consortium (W3C). A new version of HTML called HTML 4.0 has recently been officially recommended by W3C, making this level an effective standard. However, both Netscape and Microsoft browsers currently implement some features differently and provide non-standard extensions. Web developers using the more advanced features of HTML 4 may have to design pages for both browsers and send out the appropriate version to a user. Significant features in HTML 4 are sometimes described in general as dynamic HTML.

HTML Reference Manual A Beginner's Guide to HTML Background Colors Windows Based HTML Editors Take Ten Minutes to Learn HTML World Wide Web Consortium's section on Hypertext Markup Language Official W3C HTML 4.0 Specification Adobe's Pagemill Microsoft's FrontPage

JavaScript

What is JavaScript? JavaScript is an interpreted programming or script language from Netscape. It is somewhat similar in capability to Microsoft's Visual Basic, Sun's Tcl, the Unix-derived Perl, and IBM's REXX. In general, script languages are easier and faster to code in than the more structured and compiled languages such as C and C++. Script languages generallly take longer to process than compiled languages, but are very useful for shorter programs. JavaScript is used in Web site development to do such things as: Automatically change a formatted date on a Web page, Cause a linked-to page to appear in a popup window, Cause text or a graphic image to change during a mouse rollover. JavaScript uses some of the same ideas found in Java, the compiled object-oriented language derived from C++. JavaScript code can be imbedded in HTML pages and interpreted by the Web browser (or client). JavaScript can also be run at the server as in Microsoft's Active Server Pages (ASPs) before the page is sent to the requestor. Both Microsoft and Netscape browsers support JavaScript, but sometimes in slightly different ways.

The Hot Java Browser A JAVA Environment JAVA Tools Cyber JAVA - A pioneer in the Internet cafe business. Internet Tools: JAVA links the Netscape JavaScript Tutorial The JavaScript Source not only provides guidance but includes a "cut-and-paste" library of ready-made or easily adapted JavaScript code sequences. WebCoder.com A Beginner's Guide to JavaScript webreference.com's JavaScript Tips of the Week developer.com's JavaScript how-to and help Experts Exchange

What is Java? Java is a programming language expressly designed for use in the distributed environment of the Internet. It was designed to have the "look and feel" of the C++ language, but it is simpler to use than C++ and enforces a completely object-oriented view of programming. Java can be used to create complete applications that may run on a single computer or be distributed among servers and clients in a network. It can also be used to build small application modules or applets for use as part of a Web page. Applets make it possible for a Web page user to interact with the page. The major characteristics of Java are: The programs you create are portable in a network. Your program is compiled into Java bytecode that can be run anywhere in a network on a server or client that has a Java virtual machine. The Java virtual machine interprets the bytecode into code that will run on the real computer hardware. This means that individual computer platform differences such as instruction lengths can be recognized and accommodated locally just as the program is being executed. Platform-specific versions of your program are no longer needed, The code is "robust" here meaning that, unlike programs written in C++ and perhaps some other languages, the Java objects can contain no references to data external to themselves or other known objects. This ensures that an instruction can not contain the address of data storage in another application or in the operating system itself, either of which would cause the program and perhaps the operating system itself to terminate or "crash." The Java virtual machine makes a number of checks on each object to ensure integrity, Java is object-oriented, which means that, among other characteristics, similar objects can take advantage of being part of the same class and inherit common code. Objects are thought of as "nouns" that a user might relate to rather than the traditional procedural "verbs." A method can be thought of as one of the object's capabilities or behaviors, In addition to being executed at the client rather than the server, a Java applet has other characteristics designed to make it run fast, Relative to C++, Java is easier to learn. (However, it is not a language you'll pick up in an evening!). Java was introduced by Sun Microsystems in 1995 and instantly created a new sense of the interactive possibilities of the Web. Both of the major Web browsers include a Java virtual machine. Almost all major operating system developers (IBM, Microsoft, and others) have added Java compilers as part of their product offerings. The Java virtual machine includes an optional just-in-time (JIT) compiler that dynamically compiles bytecode into executable code as an alternative to interpreting one bytecode instruction at a time. In many cases, the dynamic JIT compilation is faster than the virtual machine interpretation. JavaScript should not be confused with Java. JavaScript, which originated at Netscape, is interpreted at a higher level, is easier to learn than Java, but lacks some of the portability of Java and the speed of bytecode. Because Java applets will run on almost any operating system without requiring recompilation and because Java has no operating system-unique extensions or variations, Java is generally regarded as the most strategic language in which to develop applications for the Web. (However, JavaScript can be useful for very small applications that run on the Web client or server.)

Sun Microsystems' Java page Gamelan: The Java Directory

Perl

What is Perl? (Practical Extraction and Report Language) Perl is an interpreted programming language similar to the C language but including a number of popular UNIX facilities such as sed, awk, and tr. It is regarded as a good choice for developing Common Gateway Interface (CGI) programs because it has good text manipulation facilities (although it also handles binary files). In general, Perl is easier to learn and faster to code in than the more structured, compiled C and C++ languages. Perl programs can, however, be quite sophisticated. Perl tends to have devoted adherents. Although it has the 'power' and flexibility of C, it is not fast enough to serve big databases. For this you must use C.

Our Perl Tour How to Set up Forms Available Perl Services Perl Meta-FAQ Perl Archive Perl References Take 10 Minutes to Learn Perl perlWWW (http://www.oac.uci.edu/indiv/ehood/perlWWW/) Perl Language Home Page

SGML

What is SGML? SGML (Standard Generalized Markup Language) is a standard for how to specify a document markup language or tag set. Such a specification is itself a document type definition (DTD). SGML is not in itself a document language, but a description of how to specify one. It is a metalanguage. SGML is based on the idea that documents have structural and other semantic elements that can be described without reference to how such elements should be displayed. The actual display of such a document may vary, depending on the output medium and style preferences. Some advantages of documents based on SGML are: They can be created by thinking in terms of document structure rather than appearance characteristics (which may change over time), They will be more portable because an SGML compiler can interpret any document by reference to its document tag definition (DTD), Documents originally intended for the print medium can easily be re-adapted for other media, such as the computer display screen. > The language that this Web browser uses, Hypertext Markup Language (HTML), is an example of an SGML-based language. There is a document type definition for HTML (and reading the HTML specification is effectively reading an expanded version of the document type definition). SGML is based somewhat on earlier generalized markup languages developed at IBM, including General Markup Language (GML) and ISIL.

How SGML Gets Documents into Shape SoftQuad The SGML Environment SGML Resources Information on SGML SGML: Getting Started W3 Overview of SGML Resources ISO SGML standard order (expensive)

SHTML

What is SHTML? A Web file with the suffix of ".shtml" (rather than the usual ".htm") indicates a file that includes some information that will be added "on the fly" by the server before it is sent to you. A typical use is to include a "Last modified" date at the bottom of the page. This HTTP facility is referred to as a server-side include. (Although rarely done, the server administrator can identify some other file name suffix than ".shtml" as a server-side include file.) You can think of a server-side include as a limited form of Common Gateway Interface (CGI) application. In fact, the CGI is not used. The server simply searches the server-side include file for CGI environment variables, and inserts the variable information in the places in the file where the "include" statements have been inserted.) When creating a Web site, a good idea is to ask your server administrator which environment variables can be used and whether the administrator can arrange to set the server up so that these can be handled. Your server administrator should usually be able to help you insert the necessary include statements in an HTML file.

VBScript

What is VBScript? VBScript is a Scripting Language, designed by Microsoft, based on Visual Basic which allows you to interact and communicate, more effenciently with other people around the world, on the World Wide Web. With VBScript, you have the capabilites to create animated pictures, sound files and calculations that are interactive. You can view VBScript with Microsoft Internet Explorer only. It is comparable to: Netscape's JavaScript, Sun Microsystem's Tcl, The Unix-derived Perl, IBM's REXX.

Microsoft VBScript Tutorial

What is Visual Basic? Visual Basic is a programming environment from Microsoft in which a programmer uses a graphical user interface to choose and modify preselected chunks of code written in the BASIC programming language, taken from the bases of GWBasic and BASICA. Since Visual Basic is easy to learn and fast to write code with, it's sometimes used to prototype an application that will later be written in a more difficult but efficient language. Visual Basic is also widely used to write working programs. Microsoft says that there are at least 3 million developers using Visual Basic.

Visual Basic Web Directory Microsoft's Visual Basic home page Visual Basic FAQ site

VRML

What is VRML? VRML (Virtual Reality Modeling Language) is a language for describing three-dimensional (3-D) image sequences and possible user interactions with them. Using VRML, you can build a sequence of visual images into Web settings with which a user can interact by viewing, moving, rotating, and otherwise interacting with an apparently 3-D scene. For example, you can view a room and use controls to move the room as you would experience it if you were walking through it in real space. To view a VRML file, you need a VRML viewer or browser, which can be a plug-in for a Web browser you already have. Among viewers you can download for the Windows platforms are blaxxun's CC Pro, Platinum's Cosmo Player, WebFX, WorldView, and Fountain. Whurlwind and Voyager are two viewers for the Mac.

VRML Browsers: World ViewLive 3DPioneer CC Pro viewer VRML Web Pages: VRML Browsing and Building Cyberspace Creating a VRML World Liquid Reality Black Sun InteractiveVRML Foundry Netscape's Beginner's Guide to VRML VRML Consortium VRML Repository

XML

What is XML? VRML XML (Extensible Markup Language) is a flexible way to create information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere. For example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, and so forth) and then describe the product information format with XML. Such a standard way of describing data would enable a user to send an intelligent agent (a program) to each computer maker's Web site, gather data, and then make a valid comparison. XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way. XML is currently a formal recommendation from the World Wide Web Consortium as a way to make the Web a more versatile tool. XML is similar to the language of today's Web pages, HTML, in that both contain markup symbols to describe the contents of a page or file. HTML, however, describes the content of a Web page (mainly text and graphic images) only in terms of how it is to be displayed and interacted with. For example, a <P> starts a new paragraph. XML describes the content in terms of what data is being described. For example, a <PHONENUM> could indicate that the data that followed it was a phone number. This means that an XML file can be processed purely as data by a program or it can be stored with similar data on another computer or, like an HTML file, that it can be displayed. For example, depending on how the application in the receiving computer wanted to handle the phone number, it could be stored, displayed, or dialed. XML is "extensible" because, unlike HTML, the markup symbols are unlimited and self-defining. XML is actually a simpler and easier-to-use subset of the Standard Generalized Markup Language (SGML), the standard for how to create a document structure. It is expected that HTML and XML will be used together in many Web applications. Early applications of XML include Microsoft's Channel Definition Format (CDF), which describes a channel, a portion of a Web site that has been downloaded to your hard disk and is then is updated periodically as information changes. A specific CDF file contains data that specifies an initial Web page and how frequently it is updated. Another early application is ChartWare, which uses XML as a way to describe medical charts so that they can be shared by doctors. Applications related to banking, e-commerce ordering, personal preference profiles, purchase orders, litigation documents, part lists, and many others are anticipated.

W3 Extensible Markup Language (XML) Robin Cover's XML resources page Microsoft's XML definition standards proposal

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