XSLT variable not recognized

I’ve worked with XSLT variables before, but for some reason, I can not get the stylesheet to see an assigned variable. When I copy sample code it seems to work, so it has to be something I’m doing wrong. Below is the code.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="3.0">
    <xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes" />
    <xsl:template match="/JDF">
    <xsl:variable name="customer" 
        select="/JDF/ResourcePool[1]/CustomerInfo[1]/@CustomerID"/>
            <job>
                <jobInfo>$customer</jobInfo>
            </job>
    </xsl:template>
</xsl:stylesheet>

When I run the above the result is this.

<?xml version="1.0" encoding="UTF-8"?>
<job>
   <jobInfo>$customer</jobInfo>
</job>

>Solution :

Change

<jobInfo>$customer</jobInfo>

to

<jobInfo>
  <xsl:value-of select="$customer"/>
</jobInfo>