Each web site has an address, or Uniform Resource Locator (URL). The URL contains a set of instructions that are read by the browser. The beginning of the URL contains the protocol. This is usually "http" (Hypertext Transfer Protocol) or "ftp" (File Transfer Protocol). The second section of the URL reveals the domain. Directories follow the domain. Lastly is the name of the document. (If no document is named the browser will automatically open any document in the directory named "default" or "index."