HTML to xhtml

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HTML to xhtml

• from old to new

Web Publishing
Randy Smith
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What language should be used?

• HyperText Markup Language as skeleton
• Other embedded code or references
• Scripts
• Helper apps
• References
• Server extensions
• Version of HTML
• XML (eXtensible Markpup Language)
• XHTML

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What is different about xhtml?

• HTML was designed to display data
• W3C defined Extensible Markup Language (XML) to
  describe data
• Documents and Document Type Definition (DTD)
• Collection of XML declarations that defines the
  legal structure, elements, and attributes
  available
• Content and Structure
• HTML 4 is not XML compliant

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XHTML simply refines HTML(and is intended to
replace)

• A Reformulation of HTML 4 in XML 1.0
• Almost identical to HTML 4.01, but is stricter
• Use of Document Type Definitions
• XML namespaces
• Well-formed documents
• Every element must be terminated
• Containers must nest properly
• All tags lowercase
• Attribute values must be quoted
• Name attribute is deprecated

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Conversion HTML to xhtml

• Begin with a declaration for XML version
• lt?xml version"1.0" encoding"UTF-8"?gt
• XHTML documents must reference one of the three
  XHTML DTDs
• Strict
• Transitional
• Frameset
• First line of the HTML document must declare the
  compliance type (FrontPage is little help for
  this)

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Strict XHTML compliance

• lt!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
  Strict//EN" "http//www.w3.org/TR/xhtml1/DTD/xhtml
  1-strict.dtd"gt
• Used when you're doing all of your formatting
  in Cascading Style Sheets (CSS). In other words,
  you aren't using ltfontgt and lttablegt tags to
  control how the browser displays your documents.

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Transitional doctype declaration

• lt!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
  Transitional//EN" "http//www.w3.org/TR/xhtml1/DT
  D/xhtml1-transitional.dtd"gt

Used when you need to use presentational
markup in your document. Most of us will be using
the transitional DTD for quite some time, because
we don't want to limit our audience to users with
browsers that support CSS.
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Frameset declaration

• lt!DOCTYPE html PUBLIC "-//W3C//DTDXHTML 1.0
  Frameset//EN" "http//www.w3.org/TR/xhtml1/DTD/xht
  ml1-frameset"gt
• Used when your documents have frames

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Root element must designate the XHTML 1.0
namespace

• Root element of the document must be lthtmlgt and
  must designate the XHTML 1.0 namespace
• Nothing before opening lthtmlgt tag (except the
  doctype declaration), and nothing after the
  closing lt/htmlgt tag
• Include a new namespace attribute xmlns in the
  opening HTML tag.
• lthtml xmlnshttp//www.w3.org/1999/xhtml
  xmllangen-US langengt

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Well-formed documents

• lthtmlgt
• ltheadgt
• lttitlegt
• title must be present
• lt/titlegt
• ...
• lt/headgt
• ltbodygt
• ...
• lt/bodygt
• lt/htmlgt

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Every element must be terminated

• All tags must be containers
• lthtmlgt. . .lt/htmlgt
• ltpgt. . .lt/pgt

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Containers must nest properly

• No containers may overlap
• Technically illegal in HTML, most browsers will
  allow
• ltpgtThis is ltbgtboldlt/pgtlt/bgt
• Close tags in proper order
• ltpgtThis is ltbgtboldlt/bgtlt/pgt

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All tags must be lowercase

• HTML allowed tags to be upper or lowercase
• XHTML requires tags to be lowercase
• Use a replace tool to ensure lowercase tags
• MS FrontPage
• Tools
• Page Options
• HTML Source
• Tags are lowercase

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All Attributes must be quoted

• Most browser implementations allow attributes to
  work without quotes after the assignment
• ltp aligncentergt
• ltheight50gt
• XHTML requires quotes
• ltp aligncentergt
• ltheight50gt

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Name Attribute is deprecated

• Name attribute used to identify some tag objects
• ltframegt
• ltiframegt
• ltimggt
• ltmapgt
• Name replaced with id in XHTML
• Some browsers do not support ID, so safer to
  use both
• ltimg srclogo.gif idlogo namelogo ... /gt

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Validate with a service

• http//validator.w3.org/check/referer
• http//validator.w3.org/file-upload.html