获取javascript参数的XPath查询

I've just started using XPath queries in php and while a lot is very self-explanatory I'm wordering if it's possible to get the values of an onclick() function.

An example

<a id="moreButton" onclick="showMore('#content','/page/2');">Show More</a>

The best I have come up with is //a[@id='moreButton']/@onclick which returns showMore('#content','/page/2');

Can I further refine it to only return /page/2 or will I just have to use php to parse what I have?

You must parse it with something else, XPath doesn't understand JavaScript

Actually, this can be produced by evaluating the following XPath expressions:

For the first argument of the function specified in the onclick attribute:

substring-before(substring-after(/*/@onclick, '('), ',')

For the second argument of the function specified in the onclick attribute:

substring-before(
     substring-after(substring-after(/*/@onclick, '('), ','),
     ')'
                )

XSLT - based verification:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="/">
  <xsl:copy-of select=
   "substring-before(substring-after(/*/@onclick, '('), ',')
   "/>
  ===========

   <xsl:copy-of select=
   "substring-before(
         substring-after(substring-after(/*/@onclick, '('), ','),
         ')'
                    )
   "/>

 </xsl:template>
</xsl:stylesheet>

When this transformation is applied on the provided XML document:

<a id="moreButton"
  onclick="showMore('#content','/page/2');">Show More</a>

the two XPath expressions are evaluated and the result of this evaluation is copied to the output:

'#content'
===========

'/page/2'