Several attributes can be grouped together and then used at once with xsl:attribute-set and xsl:use-attribute-sets : attribute set « XSLT stylesheet « XML Tutorial

1. XML Tutorial
2. XSLT stylesheet
3. attribute set

File: Data.xml
<?xml version="1.0" encoding="utf-8"?>
<data>
  <TITLE>GREETING</TITLE>
  <TEXT>Hello, world!</TEXT>
</data>

File: Transform.xslt

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
      version="1.0"
      xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match=" TITLE">
      <H1 xsl:use-attribute-sets="titleStyle">
        <xsl:value-of select="."/>
      </H1>
    </xsl:template>
    <xsl:template match=" TEXT">
      <P xsl:use-attribute-sets="textStyle">
        <xsl:value-of select="."/>
      </P>
    </xsl:template>
    <xsl:attribute-set name="titleStyle">
      <xsl:attribute name="align">center</xsl:attribute>
      <xsl:attribute name="style">color:red</xsl:attribute>
    </xsl:attribute-set>
    <xsl:attribute-set name="textStyle">
      <xsl:attribute name="align">right</xsl:attribute>
      <xsl:attribute name="style">color:blue</xsl:attribute>
    </xsl:attribute-set>
</xsl:stylesheet>
Output:

<?xml version="1.0" encoding="UTF-8"?>
  <H1 align="center" style="color:red">GREETING</H1>
  <P align="right" style="color:blue">Hello, world!</P>