Describe Server-side and Client-side Applications

Applications are software programs that enable specific functionality. In Web interactions, applications can reside on a Web server (back end) or on a client (front end), or in both places: partly on a client and partly on a server.

Application	Function	Example
Web server software	Processes client requests for web resources	Apache, Nginx, IIS, Tomcat
CGI (Common Gateway Interface)	Specification that enables transactions between a web server and other programs on the server (.i.e. quizzes)	SEOTrance: Information request HTML form (PHP script connects the form to the server to generate a response)
ODBC (Open Database Connectivity)	Allows for standardized access to multiple (DBMS) Database Managements Systems	SEOTrance Extranet: Search and supply forms launch ODBC via SQL to access SEOTrance databases SEOTrance internet site catalog page: Pictures of ecommerce are served from MySQL
JDBC (Java Database Connectivity)	Enables database connectivity for application written in Java	SEOTrance intern (Stock quotes)

In the Web Interaction Model, server-side applications support the Signs and Metaphors and Information Architecture layers. For example, Web server software delivers Web pages and other resources that contain Signs and Metaphors. Likewise, ODBC supports Information Architecture by providing access to databases for such navigational/informational features as searches.Some basic client-side applications are listed in the table below:
Client-side Applications

Application	Function	Example
Browser	Interprets and displays HTML documents and other resources	Chrome, Firefox, Opera
Plug-in	Extends the functionality of a browser in support of multimedia resources	Real Audio
CSS (Cascading Style Sheets)	Specification that enhances a browser's ability to display complex screen layout (i.e. placement of objects in specific locations)	w3.org

Client-side applications also support the top layers of the f . Plug-ins, browsers, and CSSs all display and interpret Signs and Metaphors, including multimedia. Information Architecture is supported by the browser, which both structures information and facilitates navigation.
The following diagram below shows the ways in which software applications work together in a Web interaction:

Client	Signs are visual markings or sounds that present information. Metaphors cue users about the functionality of the site through the use of icons or images. Together, Signs and Metaphors create the look and feel of the site.
Browser	Information Architecture organizes Signs and Metaphors into a cohesive structure. In addition, it lays down the path for navigating through the site.
Internet cloud	Software comprises underlying components (applications) that enable the display of Signs and Metaphors. In addition, software creates, stores, and manages all resources available over the Web.
Web Server and software	A network is a series of computers that communicate with each other. Common protocols used on the Internet are TCP, IP, HTTP, FTP, and SMTP (the Internet email protocol).
HTML documents, web resources	Hardware includes the user's computer equipment, also Web servers, database servers, mail servers, domain name servers, and firewall servers. On the network side, hardware includes modems, routers, hubs, and other network equipment; phone lines; and data lines (DSL, T1, OC12, etc.).
Applications	Hardware includes the user's computer equipment, also Web servers, database servers, mail servers, domain name servers, and firewall servers. On the network side, hardware includes modems, routers, hubs, and other network equipment; phone lines; and data lines (DSL, T1, OC12, etc.).
Databases	Hardware includes the user's computer equipment, also Web servers, database servers, mail servers, domain name servers, and firewall servers. On the network side, hardware includes modems, routers, hubs, and other network equipment; phone lines; and data lines (DSL, T1, OC12, etc.).

Because browser middleware can be very complex, for this lesson you will need only definitional knowledge of what it is. An analogy for middleware is a translator who allows speakers of two different languages to communicate with each other. Middleware is any software application that connects two applications that are otherwise separate.

• Design and development applications Note that design and development applications fall into a slightly different category than software that enables front-end/back-end interactions. Applications such as PhotoShop are used to create the files that are transmitted and viewed by other Web software during a Web interaction. Some common design and development applications, and their functions, are included in the table below:
  Design and Development Applications

  Application	Function	Example
  Image Manipulator	Tool used to create web-enabled graphics. Allows alteration of scanned images and creation of new images.	Photoshop
  HTML Editor	Tool to generate HTML code quickly and easily (helps avoid manual coding). Visual Studio Code is a commonly used editor for HTML and JavaScript on the Front end	Dreamweaver, Visual Studio Code
  Animation Tools	Authoring tool for animation and streaming multimedia files	Adobe Animate

The series of images below illustrates the possible software applications used at the general stages of Web interaction:

In the next lesson, you will learn the role that databases play in the functionality of complex Web sites.