I have a SVG file that I want to extend by adding onclick handlers to edges and nodes. I also want to add a script tag referring to a JavaScript. The problem is that the script tag gets an empty namespace attribute added to it. I haven't found any information regarding this that I understand. Why does XSLT add an empty namespace?

XSL file:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:svg="http://www.w3.org/2000/svg"
  xmlns:xlink="http://www.w3.org/1999/xlink">

<xsl:output method="xml" encoding="utf-8" />

<xsl:template match="/svg:svg">
  <xsl:copy>
    <script type="text/ecmascript" xlink:href="base.js" /> <!-- this tag gets a namespace attr -->
    <xsl:apply-templates />
  </xsl:copy>
</xsl:template>

<!-- Identity transform http://www.w3.org/TR/xslt#copying -->
<xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

<!-- Check groups and add functions -->
<xsl:template match="svg:g">
  <xsl:copy>
    <xsl:if test="@class = 'node'">
      <xsl:attribute name="onclick">node_clicked()</xsl:attribute>
    </xsl:if>
    <xsl:if test="@class = 'edge'">
      <xsl:attribute name="onclick">edge_clicked()</xsl:attribute>
    </xsl:if>
    <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>