I'm trying create a hyperlink to a javascript function that passes a
parameter that is stored in the xml. I'm lost on how to accomplish this:

what the html should look like:
<a href ="javascript:void(0)" onclick="jsFunction('parameter')">
Call to javascript</a>

<xsl:variable name="parameter">
  <!-- construct your param here -->
</xsl:variable>

<a href ="javascript:jsFunction('{$parameter}')">
Call to javascript</a>