http://www.w3.org/1999/xhtml
element th

Model

<th
  abbr = Text
  align = <TODO local simpleType in attribute>
  axis = <TODO local simpleType in attribute>
  char = Character
  charoff = Length
  class = xs:NMTOKENS
  colspan = Number : 1
  dir = <TODO local simpleType in attribute>
  headers = xs:IDREFS
  id = xs:ID
  lang = LanguageCode
  lang = xs:language
  onclick = Script
  ondblclick = Script
  onkeydown = Script
  onkeypress = Script
  onkeyup = Script
  onmousedown = Script
  onmousemove = Script
  onmouseout = Script
  onmouseover = Script
  onmouseup = Script
  rowspan = Number : 1
  scope = Scope
  style = StyleSheet
  title = Text
  valign = <TODO local simpleType in attribute>>
((p | (h1 | h2 | h3 | h4 | h5 | h6) | div | (ul | ol | dl) | (pre | hr | blockquote | address) | fieldset | table) | form | (a | ((br | span | bdo | map) | object | img) | (tt | i | b | big | small) | (em | strong | dfn | code | q | samp | kbd | var | cite | abbr | acronym | sub | sup) | (input | select | textarea | label | button) ) | (noscript | (ins | del | script) ) )*
</th>

abbr

align

axis

char

charoff

class

colspan

dir

headers

id

lang

lang

In due course, we should install the relevant ISO 2- and 3-letter codes as the enumerated possible values . . .

onclick

ondblclick

onkeydown

onkeypress

onkeyup

onmousedown

onmousemove

onmouseout

onmouseover

onmouseup

rowspan

scope

style

title

valign

Source

<xs:element name="th">
  <xs:complexType mixed="true">
    <xs:complexContent mixed="true">
      <xs:extension base="Flow">
        <xs:attributeGroup ref="attrs"/>
        <xs:attribute name="abbr" type="Text"/>
        <xs:attribute name="axis"/>
        <xs:attribute name="headers" type="xs:IDREFS"/>
        <xs:attribute name="scope" type="Scope"/>
        <xs:attribute default="1" name="rowspan" type="Number"/>
        <xs:attribute default="1" name="colspan" type="Number"/>
        <xs:attributeGroup ref="cellhalign"/>
        <xs:attributeGroup ref="cellvalign"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>