Thank you Chriztian!

I also found that you can do it this way:

<xsl:attribute name="value">
      <xsl:value-of select="@nodeName"/><xsl:value-of select="$currentPage/@nodeName" />
   </xsl:attribute>

You're absolutely right - though it's clunkier, it has its use when you don't know the name of the attribute you're creating, e.g.:

<a href="#">
    <xsl:attribute name="data-{keyName}">
        <xsl:value-of select="$queryValue" />
    </xsl:attribute>
</a>

- or if you need to set or override an attribute only when a certain condition is met:

<li>
    <!-- Only add class on uneven nodes -->
    <xsl:if test="position() mod 2 = 1">
        <xsl:attribute name="class">odd</xsl:attribute>
    </xsl:if>
    <a href="{umbraco.library:NiceUrl(@id)}">
        <!-- Override the href on the Home node -->
        <xsl:if test="self::Home">
            <xsl:attribute name="href">/</xsl:attribute>
        </xsl:if>
    </a>
</li>

/Chriztian 

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