HTTP – Hypertext Transfer Protocol

  • Application layer protocol from the Internet Protocol suite to transfer and exchange hypermedia
  • request-response protocol based on client-server model
  • user agent (e.g. web browser) requests some resource from a server through an URL, and the web server gives and response
  • different HTTP request methods, e.g. for retrieving or submitting data (GET and POST)

HTTPS – Hypertext Transfer Protocol Secure

  • Based on HTTP
  • Adds an additional security layer of SSL or TLS
  • ensures authentication of website by using digital certificates
  • ensures integrity and confidentiality through encryption of communication
  • still possible to track IP address and port number of web server (which is why HTTPS websites are also blocked in China)

Think why China would block sites using SSL

HTML – Hypertext Mark-up Language

  • semantic markup language
  • standard language for web documents
  • uses elements enclosed by tags to markup a document

URL – Uniform Resource Locator

  • unique string that identifies a web resource
  • reference to a web resource
  • primarily used for HTTP, but also for other protocols like FTP or email (mailto)
  • includes name AND access method (e.g. ‘http://’)
  • serves as a mechanism to retrieve a resource
  • follows a specific syntax

XML – Extensible Mark-up Language

  • markup language with a set of rules defining how to encode a document
  • human-readable
  • similar to HTML in using tags
  • used for representation of arbitrary data structures

XLST – Extensible stylesheet language

  • styling language for XML used for data presentation and transformation
  • data presentation means displaying data in some format/medium, about style
  • data transformation is about parsing a source tree of nodes out and transform it into something different
  • XLST can be used to transform XML files into other XML files, HTML, PDF, PNG and others


  • interpreted programming language
  • core technology of most websites with HTML and CSS
  • high-level, dynamic and untyped; therefore relatively easy for beginners
  • allows to dynamically manipulate the content of HTML documents
  • makes websites dynamic

CSS – Cascading style sheet

  • style sheet language to describe the presentation of a mark-up document, usually HTML
  • used to create better designed websites
  • intended to separate content in presentation in HTML and CSS
  • it uses selectors to describe particular elements of a document, and gives these properties that define things ranging from font color to page position

URI – Uniform Resource Identifier

  • more general definition than URL
  • a string serving as an identifier for some resource(document, image, mailbox, video, files, etc.)

TrendOne - The Web ExpansionFigure 2: The Difference Between URLs and URIs (Daniel Miessler)

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