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Copyright © cs-tutorial.com
Introduction to Web DevelopmentIn 1990 and 1991,Tim Berners-Lee created
the World Wide Web at the European Laboratory for Particle Physics (CERN) in Geneva, Switzerland
The original purpose of the World Wide Web (WWW) was to provide easy access to cross-referenced documents that existed on the CERN computer network
Hypertext linking allows you to quickly open other Web pages
Introduction to Web Development (continued)A document on the Web is called a Web pageA Web page is identified by a unique address
called the Uniform Resource Locator (URL)A URL is also commonly referred to as a Web
addressA URL is a type of Uniform Resource
Identifier (URI)A Web site refers to the location on the
Internet of the Web pages and related files
Introduction to Web Development (continued)Web pages are displayed using a program
called a Web browserA Web server is a computer that delivers
Web pagesThe most popular Web server software is
Apache HTTP Server (Apache)The second most popular Web server is
Microsoft Internet Information Services (IIS) for Windows
GoalTo provide information to the user:-
Files holding information must be createdThese file must be store at a central location on
computerWhen required the user should be allowed to
access these file using there desktop computers
A network link must be establish between the desktop computer and the computer serving information at a central location.
Web Communication ProtocolsA Web page is identified by a unique address
called the URLEach URL consists of two basic parts:
A protocol (usually HTTP) and Either the domain name for a Web server or a
Web server’s Internet Protocol addressHypertext Transfer Protocol (HTTP)
manages the hypertext links that are used to navigate the Web
Web Communication Protocols (continued)A host refers to a computer system that is
being accessed by a remote computerA domain name is a unique address used for
identifying a computer such as a Web server on the Internet
The domain identifier identifies the type of institution or organization (.biz, .com, .edu, .org)
An Internet Protocol, or IP address, is another way to identify computers or devices connected to the Internet
Web Communication Protocols (continued)An IP address consists of a series of four
groups of numbers separated by periods Each Internet domain name is associated
with a unique IP address (may be shared).HTTP is a component of Transmission
Control Protocol/Internet Protocol (TCP/IP)Hypertext Transfer Protocol Secure (HTTPS)
provides secure Internet connections for transactions that require security and privacy
Web Communication Protocols (continued)
http://www.google.com/help/index.html
Protocol Domain name Directory Filename
Client/Server ArchitectureServer (“back end”):
A database from which a client requests information
Fulfills a request for information by managing the request or serving the requested information to the client
Responsible for data storage and managementA system consisting of a client and a server is
known as a two-tier system
Client/Server Architecture (continued)Client (“front end”):
Presents an interface to the userGathers information from the user, submits it
to a server, then receives, formats, and presents the results returned from the server
Client/Server Architecture (continued)A three-tier, or multi-tier, client/server
system consists of three distinct pieces:Client tier, or user interface tier, is the Web
browser Processing tier, or middle tier, handles the
interaction between the Web browser client and the data storage tier Performs necessary processing or calculations
based on the request from the client tier Handles the return of any information to the client
tier
Client/Server Architecture (continued)
HTML DocumentsWeb pages are created using Hypertext
Markup Language (HTML)Web pages are commonly referred to as
HTML pages or documentsA markup language is a set of characters or
symbols that define a document’s logical structure
HTML is based on an older language called Standard Generalized Markup Language (SGML)
HTML Documents (continued)Like SGML, HTML was originally designed
as a way of defining the elements in a document independent of how they would appear
HTML has evolved into a language that defines how elements should appear in a Web browser
Understanding HTML is critical in learning how to write a web application along with the server programming
Cascading Style SheetsA single piece of CSS formatting information,
such as text alignment, is referred to as a style
The term cascading refers to the ability for Web pages to use CSS information from more than one source
Cascading Style Sheets (continued)CSS properties:
CSS styles are created with two parts separated by a colon
The property refers to a specific CSS style The value assigned to it determines the style’s
visual characteristicsTogether, a CSS property and the value
assigned to it are referred to as a declaration or style declaration
Cascading Style Sheets (continued)Inline Styles
Allow you to add style information to a single element in a document
Internal Style SheetsCreate styles that apply to the entire document
P { color : blue }selector property value
External Style SheetsA separate text document containing style
declarations that are used by multiple documents on a Web site
JavaScript and Client-Side ScriptingJavaScript is:
A client-side scripting language that allows Web page authors to develop interactive Web pages and sites
Used in most Web browsers including Firefox and Internet Explorer
Client-side scripting is a language that runs on a local browser (on the client tier) instead of on a Web server (on the processing tier)
JavaScript and Client-Side Scripting (continued)JavaScript allows you to:
Turn static Web pages into applications such as games or calculators
Change the contents of a Web page after a browser has rendered it
Create visual effects such as animationControl the Web browser window itself
Server-Side Scripting and PHPServer-side scripting refers to a scripting
language that is executed from a Web serverHypertext Preprocessor (PHP) is a server-
side scripting language that is used to develop interactive Web sitesIs easy to learnIncludes object-oriented programming capabilitiesSupports many types of databases (MySQL, Oracle,
Sybase, ODBC-compliant)
Server-Side Scripting and PHP (continued)PHP (continued):
PHP is an open source programming language Open source refers to software where source
code can be freely used and modifiedCan’t access or manipulate a Web browser like
JavaScriptExists and executes solely on a Web server,
where it performs various types of processing or accesses databases
Server-Side Scripting and PHP (continued)
General rule: Use client-side scripting to handle user interface processing and light processing, such as validation; use server-side scripting for intensive calculations and data storage