Web Technology - Old Questions
13. Write short notes on:
a) POP
b) XPath
a) POP
POP (Post Office Protocol) is also called as POP3 protocol. This is a protocol used by a mail server in conjunction with SMTP to receive and holds mails for hosts.
POP3 mail server receives e-mails and filters them into the appropriate user folders. When a user connects to the mail server to retrieve his mail, the messages are downloaded from mail server to the user's hard disk.
b) XPath
XPath is an official recommendation of the World Wide Web Consortium (W3C). It defines a language to find information in an XML file. It is used to traverse elements and attributes of an XML document. XPath provides various types of expressions which can be used to enquire relevant information from the XML document.
- Structure Definitions − XPath defines the parts of an XML document like element, attribute, text, namespace, processing-instruction, comment, and document nodes
- Path Expressions − XPath provides powerful path expressions select nodes or list of nodes in XML documents.
- Standard Functions − XPath provides a rich library of standard functions for manipulation of string values, numeric values, date and time comparison, node and QName manipulation, sequence manipulation, Boolean values etc.
- Major part of XSLT − XPath is one of the major elements in XSLT standard and is must have knowledge in order to work with XSLT documents.
- W3C recommendation − XPath is an official recommendation of World Wide Web Consortium (W3C).