How the web works: How the web works
Anatomy of a web page: Anatomy of a web page HTML or XHTML is the language used to write web pages. HTML stands for Hypertext Markup Language which is basically a language that you can use to markup or format hypertext. XHTML or HTML pages can be written in word processing programs or in WYSIWYG programs like Dreamweaver. All information in a web page is saved as text including links to other pages and images.
Anatomy of a web page: Anatomy of a web page Text paths indicate where images can be found Colors are indicated by number Live text is included as text
Anatomy of a web page: Anatomy of a web page blog.html The text file is edited and saved on your local computer. The files and folders of your website are uploaded to a web server via an ftp program. Your local computer Remote web server ~sweeneys blog.html blog.html ~sweeneys
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered Step 1 User enters in URL ~sweeneys blog.html
URL: Uniform Resource Locator: URL: Uniform Resource Locator http:// www.mccc.edu/ ~sweeneys/ blog.html Directory (folder name) File name & type Domain name Protocol (hypertext transfer protocol)
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered Step 2 User request is routed to a Domain Name Server ~sweeneys blog.html
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered Step 3 Domain Name Server translates domain name into IP address and routes the request to correct web server www.mccc.edu=198.133.170.1 ~sweeneys blog.html
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered 198.133.170.1 ~sweeneys blog.html Step 4 Web server locates the correct folder & file. If no file is specified it will display the index.html file.
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered 198.133.170.1 blog.html Step 5 Web server sends the file back to user
How a web page is delivered: Users Domain Name Server Web Server How a web page is delivered 198.133.170.1 Step 6 User’s web browser interprets HTML and displays it
User display factors: User display factors What are some of the factors that make a web page display differently?
User display factors: User display factors Browser Internet Explorer Firefox Safari Chrome Mozilla Opera Netscape AOL PDA Browsers Courtesy of W3.org
User display factors: User display factors Screen size & resolution 240x160 320x240 480x320 640x480 800 x 600 1024 x 768 Larger Courtesy of W3.org
User display factors: User display factors Color depth Most computers 24/32 bits: 16,777,216 colors Older computers/laptops 16bits: 65,536 colors Handheld 8 bit: 256 colors Courtesy of W3.org
User display factors: User display factors Javascript On - most computers Off - some work computers Courtesy of W3.org
User display factors: User display factors Gamma PC - 2.2 (darker) Mac - 1.8 (lighter) Courtesy of Creative Bits
User display factors: User display factors Fonts Courtesy of Browser News
User display factors: User display factors Disabilities Blind using a screen reader Difficulty reading small text Color blind (5-8% males) Hearing impaired