XML Demystified

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XML Demystified

• Mike Moskowitz
• Jetstream Software, Inc.
• http//www.jetsoft.com
• January 2001

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questions, questions

• XML the answer to our problems? Or just hype?
• XML a replacement for HTML? Or something
  different?
• XML a Microsoft conspiracy? Or open standard?
• XML just for programmers? Or web developers
  too?

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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We wont cover

• XML Reference
• Heavy XML programming
• Schemas, DTDs

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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How we got here

• Markup languages
• HTML

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Markup languages

• What is a markup language?
• Instructions interspersed among content
• that is one BbitchinB car, dude!M
• Some examples
• Runoff, TeX, RTF
• Who are these instructions for?

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Whats great about HTML?

• the best-known markup language
• Plain Text
• Simple
• Easy to Parse
• Standard
• Hypertext

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HTML parts of speech

• lth1gtWork Experiencelt/h1gt
• ltimg srclogo.gif width100 height20gt
• ltoption IDcurrentday selectedgtTodaylt/optiongt
• lta hrefaboutus.htmgt
• ltimg srclogo.gifgtltbrgt
• ltbgtAbout Jetstreamlt/bgt
• lt/agt

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Types of Tags

• Structural
• lth1gt, lth2gt, ltpgt, ltligt, ltstronggt
• Formatting
• ltbgt, ltigt, ltfontgt
• Semantic
• ltcitegt

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Whats not great about HTML?

• Formatting mixed with content
• Lack of semantic tags
• Not extensible

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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XML

• eXtensible Markup Language
• Exactly like HTML, only completely different
• Lets take a look

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Well-formed XML

• Processing instruction
• lt?xml version1.0?gt
• Single root element
• Case sensitive
• Tags must be closed (even empty tags)
• Tags must not overlap
• Attributes must be quoted and nonempty

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What is XML really?

• XML is a meta-markup language
• A set of rules
• No built-in tags
• Pretty useless on its own
• Foundation for writing new markup languages

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XML-based markup languages

• Chemical Markup Language (CML)
• Voice Markup Language (VoxML)
• MathML
• MusicML
• Resource Description Format (RDF)
• Wireless Access Protocol (WAP)

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Designing Markup languages

• ResumeML

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Why is this better?

• More meaningful tags
• Cleaner, clearer
• Formatting separate from content
• Where is the structure?
• Birth of a file format?

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Validating Markup languages

• DTDs
• Schemas

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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Displaying XML

• CSS and XML
• CSS in HTML vs XML
• Limits of CSS

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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XSLTransformations

• Transformations are XML to XML
• Template-matching language
• XSL is very powerful, complex

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XHTML

• Follow XML syntax
• Close tags
• Close Empty tags (really!)
• Quote attributes
• Dont overlap tags
• Lowercase tags
• Use an HTML checker

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What well cover

• How we got here
• XML basics
• Displaying XML
• Transforming XML
• XML and the web

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Where to go from here

• Where might you use XML?
• Browser display
• File formats
• Server transfer
• Database
• Client to Server input
• Server to Client results

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Where to go from here

• Web Developers
• - IE5
• XML support
• Funky XSLT support
• Good CSS1 support
• No XSL formatting objects
• IE5.5
• XML support
• Pretty good XSLT support
• Good CSS1 support
• Some CSS2 support
• Still no XSL formatting objects

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Where to go from here

• Web Developers
• - NS4
• No XML support
• Good CSS1 support
• NS6
• XML support
• Pretty good XSLT support
• Good CSS1 support
• Some CSS2 support
• Still no XSL formatting objects
• But really too soon to tell

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Where to go from here

• Server Developers
• - IIS
• Download latest MSXML package
• You can use anything you want
• Java Servers
• Check out SAX

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Resources

• W3C www.w3c.org
• Microsoft msdn.microsoft.com/xm
• Wrox Press www.wrox.com

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Questions, Comments?

• Mikem_at_jetsoft.com