URI

• https://en.wikipedia.org/wiki/Uniform_Resource_Identifier

URL

• https://en.wikipedia.org/wiki/URL

URL Example

https://example.com:445/my-documents/1234?permission=view#intro

• https: protocol or scheme
• :: separator
• //: separator
• authority component
  • example.com: hostname which will be resolved to IP address
    • IP address can be used directly
  • 445: port
• /my-documents/1234: path component
  • starts with slash /
• ?permission=view: query component
  • starts with question-mark ?
  • attribute value pairs separated by delimiters
  • common delimiters are & and ;
• #intro: fragment component
  • starts with hash #
  • for direction to resource inside the webpage, like section heading