How to read a query string with XSL

Posted on 2004-08-09
Last Modified: 2012-05-07
I need to get a value from a query string and use it in an xsl:if statment.  How is this done.  I am running my app on Apache.
Question by:bzak
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LVL 26

Expert Comment

ID: 11753831
I'm not sure this is possible directly in the XSLT with XSLT processors that would run on Apache, but here's one way to do it using MSXML:

The "right" way to do it is to pass the query string in server-side as a parameter to the transform.  But this would require some sort of server-side scripting/programming language, which you haven't mentioned.   Here's how I've done it client-side, using IE6:

function getParam(strParam)
      strQueryString = decode(;
      iTerm = strQueryString.indexOf(strParam + "=")
      if (iTerm != -1)
            strSubQuery = strQueryString.substring(iTerm + strParam.length + 1)
            iTermEnd = strSubQuery.indexOf("&")
            if (iTermEnd == -1)
                  iTermEnd = strSubQuery.length
            strSubQuery = strSubQuery.substring(0, iTermEnd)
            strSubQuery = null
      return strSubQuery
// URL Decodes the string
function decode(str) {
     return unescape(str.replace(/\+/g, " "));

Then when calling the transform, you add the parameter to the XSLT like:

xslProc.addParameter("pMyParam", getParam('foo'));

Mike Sharp

Author Comment

ID: 11754000
How do I use:

xslProc.addParameter("pMyParam", getParam('foo'));

in an xsl:if statement?
LVL 26

Expert Comment

ID: 11754222

xslProc.addParameter("pMyParam", getParam('foo'));

sets a parameter in the XSLT like:

<xsl:param name="pMyParam"/>

so that during transformation, the parameter functions as if it was created like:

<xsl:param name="pMyParam">bar</xsl:param>

Which is used like (for example, assuming the querystring was foo=bar):

<xsl:if test="$pMyParam = 'bar'">foo equals bar</xsl:if>

For a complete example of setting parameters during transformation, look at my dynamic filter and sort example:

This sets nodelists as parameters, as well, which has interesting implications.

Mike Sharp
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LVL 26

Expert Comment

ID: 11754253
In any case, you'll need to use whatever flavor of a template processor you have available to Xalan or whatever.  Just make sure it has the ability to set parameters externally.

Mike Sharp

Author Comment

ID: 11754444
Ok, now for the tricky part....

I am importing two templates into a master....

<?xml version="1.0" encoding="ISO-8859-1"?>

<xsl:stylesheet version="1.0"
<xsl:import href="fpForm_ST.xsl"/>
<xsl:import href="fpTemplate.xsl"/>

The query string variable needs to be read by fpTemplate.xsl.  This does not work.  It only works if I remove the import statement for fpForm.xsl.

Author Comment

ID: 11754943
Actually I was able to get it to work with your example:

<xsl:stylesheet version="1.0" xmlns:xsl=""
  <xsl:output method="html" indent="yes" encoding="iso-8859-1"/>
   <xsl:variable name="xmlpath" select="url:findURL(.)" />
  <xsl:variable name="search">
    <xsl:if test="contains($xmlpath,'?')">
      <xsl:value-of select="substring-after($xmlpath,'?')" />
  <msxsl:script language="JScript" implements-prefix="url">
    function findURL(nodelist)
      return nodelist.nextNode().url;

      <link href="style.css" rel="stylesheet" type="text/css" />
        <xsl:for-each select="planName">
          <xsl:text>The search string is: </xsl:text>
          <xsl:value-of select="$search" />

Bu I am not sure how to cut up the string....
I am getting:

The search string is: test1=Test&test2=test

I want to use the value of test1 in the if statement
LVL 26

Accepted Solution

rdcpro earned 350 total points
ID: 11755585
This should work:

<xsl:value-of select="substring-before(substring-after($search, 'test1'), '&amp;')"/>

Mike Sharp

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