W1. The Web Model Flashcards
What were the three main components of Tim Berners Lee’s model of the World Wide Web?
- HTML - define pages/documents of info
- URI - Uniform Resource Identifier (reference/name for a page/resource)
- HTTP - messages allowing transfer of resources across the internet
What does HTML stand for?
Hyper-Text Markup Language
What is HTML for?
Defining structure of web-pages
Uses tags to enclose static information
What is a browser’s purpose?
- a browser is a user interface engine
- renders HTML files to produce web pages
What tags are required for any HTML page?
What is a URI?
Uniform Resource Identifier
- identifies a resource
What is a URL?
Uniform Resource Locator
- identifies a resource
- locates that resource within network
- subset of URI
What is a URN?
Uniform Resource Name
- persistent, location-independent resource identifier
- subset of URI
- name with no location information
What does HTTP stand for?
Hyper Text Transfer Protocol
Properties and uses of HTTP
- stateless, application-level protocol
- text-based protocol
- protocol for transfer of resources
What are the 3 common HTTP methods invoked by client on server?
GET - client sends a request for a resource
HEAD - client requests http header info only
POST - client sends arguments in URL to be processed by server (e.g. form data)
What does CSS stand for?
Cascading Style Sheets
What is CSS used for?
CSS is used to describe presentation on web page
- separation of content from style
- layout, size, color etc for tags: relationships & selectors
- support for media and graphics
What format does CSS have?
selector { property : value ; }
How do you group multiple selectors in CSS?
Comma-separated list
