php_AppA
advertisement
Appendix A
Introduction to Web
Development
PHP Programming with MySQL
Introduction to Web Development
• In 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 crossreferenced documents that existed on the CERN
computer network
• Hypertext linking allows you to quickly open
other Web pages
PHP Programming with MySQL
2
HTML Documents
• Web pages are created using Hypertext Markup
Language (HTML)
• Web pages are commonly referred to as HTML
pages or documents
• A 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)
PHP Programming with MySQL
3
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
PHP Programming with MySQL
4
Basic HTML Syntax
• HTML documents are text documents that
contain formatting instructions called tags
• HTML tags include:
– Formatting commands (boldface or italic)
– Controls that allow user input (option buttons or
check boxes)
• Tags are enclosed in brackets (< >) and consist
of an opening tag and a closing tag
PHP Programming with MySQL
5
Basic HTML Syntax (continued)
• The closing tag must include a forward slash
( / ) immediately after the opening bracket
• A tag pair and the data it contains are referred to
as an element
• The information contained within an element’s
opening and closing tags is referred to as its
content
• Elements that do not require a closing tag are
called empty elements
PHP Programming with MySQL
6
Basic HTML Syntax (continued)
Table 1-1 Common HTML elements
PHP Programming with MySQL
7
Basic HTML Syntax (continued)
• HTML documents must have a file extension of
.html or .htm
• All HTML documents must use the <html>
element as the root element
• A root element contains all the other elements
in a document
• The <head> element contains information that is
used by the Web browser
PHP Programming with MySQL
8
Basic HTML Syntax (continued)
• A <head> element must contain a <title>
element
• The <head> element and the elements it
contains are referred to as the document head
• The <body> element and the text and elements
it contains are referred to as the document
body
• The process by which a Web browser
assembles or formats an HTML document is
called parsing or rendering
PHP Programming with MySQL
9
Basic HTML Syntax (continued)
• Example:
<p><b>This paragraph will appear in
boldface in a Web browser</b></p>
• Parameters used to configure many HTML
elements are called attributes
• Insert line breaks using the paragraph <p> and
line break <br> elements
PHP Programming with MySQL
10
Basic HTML Syntax (continued)
Sample HTML Code
<html>
<head>
<title>Toner Cartridge Sales</title>
</head>
<body>
<h1>Toner Cartridge Sales</h1>
<hr>
<h2>Lexmark Toner Cartridges</h2>
<img src="lexmark_logo.gif">
<p><b>Model #</b>:LEX 1382100<br>
<b>Compatibility</b>: Optra 4049/3112/3116<br>
<b>Price</b>: $189.99</p>
<p><b>Model #</b>:LEX 1380520<br>
<b>Compatibility</b>:Lexmark 4019/4028/4029<br>
<b>Price</b>:$209.00</p>
</body>
</html>
PHP Programming with MySQL
11
Basic HTML Syntax (continued)
Figure 1-1 A simple HTML document in a Web browser
PHP Programming with MySQL
12
Web Communication Protocols
• A Web page is identified by a unique address
called the URL
• Each 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 address
• Hypertext Transfer Protocol (HTTP) manages
the hypertext links that are used to navigate the
Web
PHP Programming with MySQL
13
Web Communication Protocols
(continued)
• A host refers to a computer system that is being
accessed by a remote computer
• A 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
PHP Programming with MySQL
14
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
• 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
PHP Programming with MySQL
15
Web Communication Protocols
(continued)
http://www.google.com/help/index.html
Protocol
Domain name
Directory
Filename
Figure 1-4 Sample URL
PHP Programming with MySQL
16
Publishing Your Web Site
• Web Hosting:
– The publication of a Web site for public access
– Internet access (cable modem, DSL, satellite,
dial-up modem, ISP)
• Internet Service Provider (ISP):
– Provides access to the Internet along with other
types of services such as e-mail
– America Online, CompuServe, and EarthLink
PHP Programming with MySQL
17
Publishing Your Web Site
(continued)
• ISP advantages to hosting a Web site:
– Extremely fast Internet connections using
advanced fiber-optic connections
– Large and powerful Web servers and the
expertise and manpower to maintain and manage
them
• A domain name is a unique address used for
identifying a computer, such as a Web server on
the Internet
PHP Programming with MySQL
18
Publishing Your Web Site
(continued)
• Domain name registration
– Pick a domain name that is similar to your
business name or that describes your Web site
– You cannot use a domain name that is already in
use or a trademarked name
– Contact a domain name registrar to find out the
availability of a domain name and register it
– Domain names are stored in a master database
that is maintained by the InterNIC
PHP Programming with MySQL
19
Publishing Your Web Site
(continued)
• Domain name registration (continued)
– For a fee, domain names can be registered for a
specified period of time
– A popular domain name registrar is Network
Solutions
– After you register your domain name, notify your
ISP of your domain information
PHP Programming with MySQL
20
Publishing Your Web Site
(continued)
• File Transfer Protocol (FTP)
– Is a TCP/IP protocol used for transferring files
across the Internet
– Transfers files between an FTP client (your
computer) and an FTP server (a server capable
of running FTP)
– The vehicle that allows you to get your Web page
files to the Web server
PHP Programming with MySQL
21
Publishing Your Web Site
(continued)
• File Transfer Protocol (continued)
– Your ISP provides a username and password to
log on to the FTP site and upload files to the FTP
server
– Examples of FTP clients include Filezilla, Firefox,
Internet Explorer
– Allows you to use your browser to log on to an
FTP server and upload your files
PHP Programming with MySQL
22
Working with Well-Formed
Web Pages
• HTML became an Internet standard in 1993 with
the release of version 1.0
• The current version of HTML (4.01) was
released in 1999
• HTML 4.01 is the last version of the HTML
language and is being replaced with extensible
hypertext markup language (XHTML)
• HTML is not suitable for user agents other than
Web browsers
PHP Programming with MySQL
23
XHTML Document Type Definitions
(DTDs)
• A well-formed document must include:
– <!DOCTYPE> declaration
– <html>, <head>, and <body> elements
• A document type definition (DTD) defines:
– The elements and attributes that can be used in
a document
– The rules that a document must follow when it
includes them
PHP Programming with MySQL
24
XHTML Document Type Definitions
(DTDs) (continued)
• There are three types of DTDs with XHTML
documents:
– transitional
– strict
– frameset
• The World Wide Web Consortium (W3C) was
established in 1994 at MIT to oversee the
development of Web technology standards
PHP Programming with MySQL
25
XHTML Document Type Definitions
(DTDs) (continued)
• The W3C:
– Decided some common HTML elements and
attributes for display and formatting would not be
used in XHTML 1.0
– Recommended using Cascading Style Sheets
(CSS) instead of HTML elements and attributes
for displaying and formatting Web pages
• Elements and attributes that are considered
obsolete and will eventually be eliminated are
said to be deprecated
PHP Programming with MySQL
26
XHTML Document Type Definitions
(DTDs) (continued)
Table 1-2 HTML elements that are deprecated in XHTML 1.0
PHP Programming with MySQL
27
XHTML Document Type Definitions
(DTDs) (continued)
• Transitional DTD:
– Allows you to use deprecated style elements in
your XHTML documents
– Use only if you need to create Web pages that
use the deprecated elements
• Frameset DTD:
– Identical to the transitional DTD, except that it
includes the <frameset> and <frame> elements
– Allows you to split the browser window into two or
more frames
PHP Programming with MySQL
28
XHTML Document Type Definitions
(DTDs) (continued)
• Strict DTD:
– Eliminates the elements that were deprecated in
the transitional DTD and frameset DTD
– The <!DOCTYPE> declaration for the strict DTD
is as follows:
<!DOCTYPE html PUBLIC
"-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
– Always try to use the strict DTD
PHP Programming with MySQL
29
Writing Well-Formed Documents
• Include a <!DOCTYPE> declaration and the
<html>, <head>, and <body> elements
• All XHTML documents must use <html> as the
root element
• XHTML is case sensitive
• All XHTML elements must have a closing tag
• Attribute values must appear within quotation
marks
PHP Programming with MySQL
30
Writing Well-Formed Documents
(continued)
• Empty elements must be closed
• XHTML elements must be properly nested
• Nesting refers to how elements are placed
inside other elements
PHP Programming with MySQL
31
Cascading Style Sheets
• A 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
PHP Programming with MySQL
32
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 characteristics
– Together, a CSS property and the value assigned
to it are referred to as a declaration or style
declaration
PHP Programming with MySQL
33
Cascading Style Sheets
(continued)
• Inline Styles
– Allow you to add style information to a single
element in a document
• Internal Style Sheets
– Create styles that apply to the entire document
P { color : blue }
selector property
value
• External Style Sheets
– A separate text document containing style
declarations that are used by multiple documents
on a Web site
PHP Programming with MySQL
34
Client/Server Architecture
• Server (“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 management
• A system consisting of a client and a server is
known as a two-tier system
PHP Programming with MySQL
35
Client/Server Architecture
(continued)
• Client (“front end”):
– Presents an interface to the user
– Gathers information from the user, submits it to a
server, then receives, formats, and presents the
results returned from the server
PHP Programming with MySQL
36
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
PHP Programming with MySQL
37
Client/Server Architecture
(continued)
Figure 1-16 The design of a three-tier client/server system
PHP Programming with MySQL
38
JavaScript and Client-Side
Scripting
• JavaScript 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)
PHP Programming with MySQL
39
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 animation
– Control the Web browser window itself
PHP Programming with MySQL
40
Server-Side Scripting and PHP
• Server-side scripting refers to a scripting language that
is executed from a Web server
• Hypertext Preprocessor (PHP) is a server-side
scripting language that is used to develop interactive
Web sites
– Is easy to learn
– Includes object-oriented programming capabilities
– Supports many types of databases (MySQL, Oracle,
Sybase, ODBC-compliant)
PHP Programming with MySQL
41
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 modified
– Can’t access or manipulate a Web browser like
JavaScript
– Exists and executes solely on a Web server,
where it performs various types of processing or
accesses databases
PHP Programming with MySQL
42
Server-Side Scripting and PHP
(continued)
Figure 1-17 How a Web server processes a PHP script
• 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
PHP Programming with MySQL
43
