xml extensible markup language erik forsström olle wessel patrik löfgren

XML

eXtensible Markup Language

Erik Forsström Olle Wessel Patrik Löfgren

XML

eXtensible Markup Language

Background

XML = HTML + SGML HTML

Unstructured No custom tags Present simple information

SGML

SGML != internet Recycling of information Structure information Intelligent information Complex

XML

Structured informaton Elements = content + tags No layout information DTD specifies structure XML schemas = DTD 2.0 Attribute Unique tags

XML on the web

XML != replacement off HTML Seperate data from HTML Store data inside HTML documents Format for exhange information Store data in files and dadabases

Conversion XML to HTML

Seding XML to PC conversion on PC

User PC

Converter fromXML to HTML

IntermediateHTML document


CSS and/or XSLLayout information

Server

XML document


Conversion on the server before transmission

User PC





XML document

Server


Conversion on the server before storage

Server




XML document



User PC

Store of prepared HTML pages

Ordinary HTTP sever dispatching web pages on request

XML and DTD

<?xml version="1.0"?>

<!DOCTYPE person SYSTEM "person.dtd"><?xml-stylesheet type="text/css"

href="unit.css"?>

<heroes>

<NAMN><FoRNAMN>James</FoRNAMN><EFTERNAMN>Bond</EFTERNAMN><adress><gata> historiegränd </gata><stad> umeå </stad></adress></NAMN>

<NAMN><FoRNAMN>Clark</FoRNAMN><EFTERNAMN>Kent</EFTERNAMN><adress><gata> fysikgränd </gata><stad> umeå </stad></adress></NAMN>

</heroes>

<!ELEMENT namn (fornamn, efternamn)><!ELEMENT adress (gata, stad)>

<!ELEMENT fornamn (#PCDATA)><!ELEMENT efternamn (#PCDATA)>

<!ELEMENT gata (#PCDATA)><!ELEMENT stad (#PCDATA)>

XML on browser

XML with style sheetheroes{background-color:

#ffffff;width: 100%;}NAMN{display: block;margin-bottom:

30pt;margin-left: 0;}EFTERNAMN{color: #FF0000;font-size: 20pt;}adress{color: #0000FF;font-size: 20pt;}STAD {color: #AAFF99;}

<?xml version="1.0"?>

<!DOCTYPE person SYSTEM "person.dtd"><?xml-stylesheet type="text/css" href="unit.css"?>

<heroes>

<NAMN><FoRNAMN>James</FoRNAMN><EFTERNAMN>Bond</EFTERNAMN><adress><gata> historiegränd </gata><stad> umeå </stad></adress></NAMN>

<NAMN><FoRNAMN>Clark</FoRNAMN><EFTERNAMN>Kent</EFTERNAMN><adress><gata> fysikgränd </gata><stad> umeå </stad></adress></NAMN>

</heroes>

www.w3schools.com

XHTML

Harder and fast syntax rules Elements properly nested Documents must be well-formed Tag names in lowercase All elements must be closed

XML user interfaces

XML for define user interfaces ZUL Easy to uppdate interfaces

The Future of XML

Relies on the big companies Unite around a few standards Early adoption to XML has risks and

oppurtunities Business to business applications

Negative aspects

Open standards may give users a feeling of lacking security

Too many XML schemas XML demands more initial work from the

developers Definitions and relations between tags

must make sense Programmers not known for careful syntactic,

grammatic and semantic correctness Old profession data analyst would be

needed again

XML on the internet

XML, HTML and other languages will interoperate, not compete

XML makes it theoretically possible to represent information differently Speech processing Braille writing

XML on the internet

Internet infrastructure will remain the same, XML is added on top

New applications RSS Metro (will compete with pdf, Microsoft

standard)