XML Form date Manipulation

Dear Experts,

In XML form builder application we need to display the current date + 14 days in the Expiry date filed. The above requirement is cannot be met directly form the XML Form builder application. We need to edit the xsl file to get it done,

<xsl:attribute name="value">

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

</xsl:attribute>

the above is the xsl code for getting current date which is working fine. Now we need to add 14 day from the current date. I tried with

<xsl:attribute name="value">

<xsl:value-of select="$locDate"+14/>

</xsl:attribute>

which is giving is NaN. Can you please help in getting this done.

Regards

Noel