1. IS1500: Introduction to Web Development
Essential Web Concepts
Martin Schedlbauer, Ph.D.

2. Essential Web Concepts
IS4300
What is the Web?
The “web” is a combination of things:
A collection of physical communication networks
4G, , T1, etc.
A collection of application communication protocols
HTTP, SMTP, FTP
A collection of languages
HTML, JavaScript, CSS, PHP, etc.
IS1500
Essential Web Concepts

3. What is Web Development?
Web development is the process of creating web sites and web applications using one or more programming languages.
Web development involves client-side (browser-side) and/or server-side programming.
IS1500
Essential Web Concepts

4. Essential Web Concepts
What do I need to learn?
That depends…
For client-side programming, you’ll need to know at least HTML, CSS, and JavaScript
For server-side programming, you’ll need to know one or more programming languages such as PHP, ASP.NET, Java, Deluge, Ruby, among many others.
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Essential Web Concepts

5. Browsers and Web Servers
The web is a simple client/server architecture where clients send requests for documents to servers generally using the HTTP protocol.
request
request
Internet
HTML Document
HTML Document
Computer with Browser
Web Server
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Essential Web Concepts

6. Essential Web Concepts
Documents
Browsers request documents from web servers.
These documents are generally HTML documents but can also be PDF documents or images, videos, and audio files.
The documents are either stored on the web server as a file or generated “on-the-fly” by a program running on the web server.
IS1500
Essential Web Concepts

7. Essential Web Concepts
Dynamic Documents
Dynamic documents are generated when requested and include information retrieved from a database at the time of generation.
This allows the HTML document (page) to have the latest information in it.
The browser always receives an HTML document; it does not care that it is generated.
IS1500
Essential Web Concepts

8. Generating Dynamic Pages
Dynamic documents are generated through a program written in any one of these languages:
PHP
Java
ASP.NET
Deluge
Ruby
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Essential Web Concepts

9. Essential Web Concepts
The URL
The URL (Uniform Resource Locator) is a standard way of specifying documents on a web server.
Examples:
is1500.weebly.com/index.html
IS1500
Essential Web Concepts

10. Essential Web Concepts
Format of the URL
The URL has a standard format, but some parts are optional and are “filled in” by the browser based on conventions:
protocol://domainOrIPAddress:port/path/filename
IS1500
Essential Web Concepts

11. Essential Web Concepts
Protocols
Indicates what protocol will be used to access the document.
Some common protocols include HTTP (Hyper Text Transfer Protocol) for transferring web content and FTP (File Transfer Protocol) for transferring files over a remote connection.
The protocol is followed by ://
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Essential Web Concepts

12. Essential Web Concepts
Supported Protocols
While not all browsers support all protocols, they generally include:
http and https
file
ftp
news
mailto
The default protocol is http.
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Essential Web Concepts

13. Essential Web Concepts
Domain or IP Address
The domain or IP address is the “address” of the web server on which the document is located.
Specified generally as a domain name in the form:
Example:
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Essential Web Concepts

14. What’s with the www Prefix?
The “www” prefix is actually only a convention.
Most companies name the computer on which their web site is stored “www”, but they don’t have to.
For example, our website is at:
is1500.weebly.com
IS1500
Essential Web Concepts

15. Essential Web Concepts
What about other TLDs?
There are many other top-level domains (TLDs) besides .com, such as:
Countries: .de, .ch., .me, .tv
Organizations: .mil, .gov, .edu, .org, .net
Categories: .biz, .info
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Essential Web Concepts

16. How do I get a domain name?
You register your domain name through a domain registration service who will then register it with ICANN and add it to the Domain Naming Service (DNS) so that browsers can find it.
Well known domain registration services:
GoDaddy
Yahoo
Weebly
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Essential Web Concepts

17. Domain Names and IP Addresses
IS4300
Domain Names and IP Addresses
The actual computers on the Internet are identified through a number rather than a domain name.
DNS translates from a domain name to an IP address.
IP Address are generally in the form:
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Essential Web Concepts

18. Essential Web Concepts
The DNS Lookup
IS1500
Essential Web Concepts

19. Finding Your Computer’s IP Address
There are several ways you can find your computer’s IP address:
Use Google: type in “what’s my ip”
Go to a “shell” or “command line”; on Windows, run “cmd” and then use the command “ipconfig”
IS1500
Essential Web Concepts

20. Essential Web Concepts
Long URLs
URLs can get pretty long when the file has a long name and is stored in a folder.
They can be shorted by a URL shortener who stores the URL and then translates so the URL is easier to type, remember, and share.
IS1500
Essential Web Concepts

21. Essential Web Concepts
URL Shorteners
Some common URL shorteners include:
bit.ly
goo.gl
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Essential Web Concepts

22. Essential Web Concepts
HTTP Protocol
User selects a document by specifying its URL
Browser formulates an HTTP request for that document and sends it to the web server specified in the URL
Server looks for the document or runs the program to generate the document
Server sends document back to browser
Browser renders (displays) document
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Essential Web Concepts

23. Essential Web Concepts
HTTP Request Sequence
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24. Connecting to the Internet
Computers connect to the Internet through a variety of networks:
Mobile networks: 4G, 3G, etc.
Telephone: ISDN, DSL
Cable
Wireless: WiFi
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25. Essential Web Concepts
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26. Essential Web Concepts
Developing for the Web
You will need:
Program to edit your HTML files
Place to store HTML file and “publish”
Register domain name of web site
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Essential Web Concepts

27. Essential Web Concepts
Our Stack I
We will use:
Weebly to edit HTML files in their “nice” and user-friendly editor that does not require knowledge of HTML
Weebly to host our web site
Weebly to provide domain name and registration
Free Weebly account is limited to 10 pages and has some other limitations.
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28. Essential Web Concepts
Our Stack II
We will also use:
AwardSpace to edit files in their HTML editor
AwardSpace to host our web site
AwardSpace to provide TLD and registration
This will be used when we want to build websites directly in HTML.
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Essential Web Concepts

29. What about Search Engines?
Search engines store “all” pages in a vast database and allow users to search the database to find what they are looking for.
Some top search engines:
Google
Bing
Yahoo
DogPile
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Essential Web Concepts

30. Summary, Review, & Questions…
IS1500
Essential Web Concepts