summary web programming introduction to web programming chapters (1)

summary web programming introduction to web programming chapters (1)

internet

Internet

millions of computers connected together in some way
example of devices ( phone lines , modems )
they can share information.
one big network of computers.

The physical structure of the Internet uses

fiber-optics cables, satellites, phone lines, and other telecommunications media that send data back and forth.
internet → network of networks
devices → PC - smart phones - modems - smart cars
structure → wired - wireless

the internet is

content providers ( web pages ) → servers
end users → client

www

World Wide Web → a collection of electronic documents that are linked together like a spider web
these documents are stored on computers called servers located around the world
Web has evolved into

a global electronic publishing medium
and increasingly → a medium for conducting electronic commerce.

website → static content - web application → dynamic content

web page

web page → an electronic document written in a computer language called HTML (Hypertext Markup Language)
Web pages can contain

text, graphics, video, animation, sound
as well as interactive features → such as data entry forms.

examples of interactive features → entering data → users enter data ( as login pages )

Each page has a unique address known as a URL (Uniform Resource Locator) → which identifies its location on the server.

URL → is the path to access a certain web page → every webpage have a unique URL
location of the URL → form the address bar

website

website → is multiple web pages that are saved in directory's and sub directory's
is there any limitation of web pages number ?

yes → and the number of web pages depend on the storage space of the server

A website → is one or more web pages that relate to a common theme, such as a person, business, organization, or a subject, such as sports.
The first page is called the home page → which acts like an index, indicating the content on the site.
From the home page → you can click hyperlinks to access other web pages.
small summary’s

Webpage (home) is a specific page within a website; Website URL is the web address for the entire site.

The website URL is usually the same as the home page, but if it's not, it could be the URL of another important page on the site.

A hyperlink is a clickable element on a webpage, and a URL specifies the web address.
"www" is a subdomain, and "http" ( hyper text transfer protocol ) or "https" are part of a URL.

The development and maintenance of web pages → in order

plan a website → ( targets - recourse - goal - budget )
analyze and design a web site → the place where we put the security principles

example : least privilege's - check user input - isolation

create a website
deploy a web site → deploy to let the website available to public
maintain a website → maintain is process of keeping a website up-to-date and running smoothly as well as performing optimally

plan → analyze and design → create → deploy → maintain

types of web sites

Portal - News - Informational - Business/Marketing - Wiki - Online Social Network - Educational - Entertainment - Web Application - Personal

Internet and web programming technologies are designed to be → portable
portable → allowing you to design web pages and applications that run across an enormous range of Internet-enabled devices

Client-side programming technologies → are used to build web pages and applications that are run on the client (in the browser on the user's device).
Server-side programming → the applications that respond to requests from client-side web browsers, such as :

searching the Internet - checking your bank-account balance - ordering a book from Amazon

HTML

HTML (Hypertext Markup Language) → is a special type of computer language called a markup language designed to :

specify the → content and structure of → web pages (also called documents) in a portable manner.

HTML5, now under development → is the emerging version of HTML.
HTML enables you to → create content that will render appropriately across the extraordinary range of devices connected to the Internet, including :

smartphones, tablet computers, notebook computers, desktop computers, special-purpose devices such as large-screen displays at concert arenas and sports stadiums, and more.

important for the exam → portable manner → run on multiple platforms OS ( Linux - iOS - etc. ) and devices
browser → is the client → to see the webpages of a website

CSS

Cascading Style Sheets (CSS) → are used to specify the presentation or styling of elements on a web page (fonts, spacing, sizes, colors, positioning).

CSS was designed to style portable web pages independently of their content and structure.
By separating page styling from page content and structure → you can easily change the look and feel of the pages on an entire website.
CSS3 → is the current version of CSS under development.

HTML5 → the structure - content of the website
CSS → the styling - design - presentation of the webpage

Cascading Style Sheets (CSS) is a simple mechanism for adding style (e.g., fonts, colors, spacing) to Web documents → one design will be imported to all the other pages not as HTML the require designing for each page

example : I have 1000 pages → I want red color the update using CSS will be applied to all the pages at once - in HTML will be applied one by one

Although HTML5 provides → some capabilities for controlling a document's presentation, it's better not to mix presentation with content.

JavaScript

JavaScript → helps you build dynamic web pages (pages that can be modified "on the fly" in response to events → such as user input, time changes, and more) and computer applications.

enables you to do the client-side programming of web applications.
JavaScript was created by Netscape.
JavaScript is a portable scripting language.
Programs written in JavaScript can run in web browsers across a wide range of devices.

JavaScript → interactive website ( entre values - retrieve values ) - dynamic web pages

W3C

World Wide Web Consortium (W3C) was founded → In October 1994

Goal of W3C → is to make the Web universally accessible regardless of disability, language, culture.
W3C → Standardization Organization.
Web technologies standardized by W3C are called → Recommendations.

Recommendations include → Hypertext Markup Language 5 (HTML5), Cascading Style Sheets 3 (CSS3), and the Extensible Markup Language (XML).

W3C → responsible for → HTML - CSS - XML

to be more compatible between between nations and devices

Extensible Markup Language (XML) lets you define and store data in a shareable manner. XML supports information exchange between computer systems such as websites, databases, and third-party applications. → tags
CSV (comma-separated values) file is a text file that has a specific format which allows data to be saved in a table structured format. → comma

what is the needed for the web

personal computer.
Web browser → software to access the Web.
connection → to an Internet service provider (ISP).
Servers → to host the data.
Routers and switches → to direct the flow of data.

There are three main ways to move between web pages or websites:

Clicking a text hyperlink.
Clicking a hyperlinked graphic image → such as a button, photograph, or drawing.
Typing the URL of a web page in the location box (also known as → the address field) of your web browser and then pressing the Enter or Return key.

how the web pages works

Web pages are stored on web servers located around the globe.
Entering the (Uniform Resource Locator) URL of a web page in your web browser or clicking a link sends a request to the server which hosts the page.
The server sends the web page to your computer, and your web browser displays it on your screen.

The Web is a client/server application → Web browsers are → clients which send requests to Web servers → which send responses back.

Different browsers → Microsoft Internet Explorer, Netscape, lynx (UNIX).
Although browsers share a common set of features, each browser might render pages differently.

browser is a client that will request the content
browser use client-server communication
note: Peer-to-Peer (P2P) Service? A peer-to-peer (P2P) service is a decentralized platform whereby two individuals interact directly with each other, without intermediation by a third party

URL

Uniform Resource Locators (URLs) are used to identify Web pages → basically a URL is a web address.
URLs have 3 components:

A Prefix → (usually http://) → data transfer protocol → required to request to the server
A Hostname → (such as www.cityu.edu.hk) → identify the computer in the internet
A Path → (such as /scm/index.htm) → identify the file in hierarchal directory structure on the server

IP - DNS

Every computer connected to the Internet must have a → unique IP address, no matter whether → it's a client or a server (or both).
An IP address → is just a number that identifies a host on the Internet.

Example: 212.171.218.34 or 144.214.5.218

The Domain Name System (DNS) → is a database that matches IP addresses to host names.
the Domain Name System (DNS) translates host names into IP addresses, which are then used by TCP to establish connections between HTTP clients and servers.
Domain names are administered in such a way that they are guaranteed to be unique.
Domain names are organized in a → hierarchical structure.

top - second - third level domain

www.apple.com
Top-level domain → country domains → important for exam

.com - Commercial, .net - Network, .gov - Government, .edu - Education, .co - Company, .jo - Jordan, .us - United States, .uk - United Kingdom, .ca - Canada, .au - Australia, .de - Germany.
.com → generic Top level domain gTDL

second level domain → actual name of the organization or service → contains : letter - 0 to 9 - dashes ( - ) → apple
third level domain → strings of character that designate different hosts within second level domain or services

www → core - main website
sweb.cityu.edu.hk → sweb → sub network within the cityu

TCP / IP

TCP → transitions Control Protocol
Messages are sent → are made up of packets which include sender IP and destination IP.
IP address internet protocol → every machine has a unique IP address.
FTP: File transfer protocol
SMTP: simple mail transfer protocol
NNTP: network news transfer protocol
HTTP: Hypertext Transfer protocol