Whitespace Handling in XSL Transformation

In XML, carriage return, linefeed, tab, and the spacebar are the whitespace characters. By default, XSLT preserves whitespaces. White-space in the stylesheet is ignored as long as it occurs between XML elements only. For example, the following XSL template:

<xsl:template match="foo">
  foo
</xsl:template>

will produce the following results from the processor's point of view.

"\n··foo\n"

To avoid the unwanted whitespaces, you should try the following XSL template

<xsl:template match="foo">
  <xsl:text>foo</xsl:text>
</xsl:template>

Also you are applying the following template

<xsl:apply-templates />

It applies to "white-space-only" nodes as well  because the default XSLT rule for text nodes says "copy them to the output". For instance:

<xml>
  <data> value </data>
</xml>

contains three text nodes:

1. "\n··" (right after <xml>)
2. "·value·"
3. "\n" (right before </xml>)

To avoid that #1 and #3 sneak into the output (which is the most common reason for unwanted spaces), you can override the default rule for text nodes by declaring an empty template:

<xsl:template match="text()" />

All text nodes are now muted and text output must be created explicitly:

<xsl:value-of select="data" />

To remove white-space from a value, you could use the normalize-space() XSLT function:

<xsl:value-of select="normalize-space(data)" />

But careful, since the function normalizes any white-space found in the string, e.g. "·value··1·" would become "value·1".

Additionally you can use the <xsl:strip-space> and <xsl:preserve-space> elements. By default, XSLT templates have <xsl:preserve-space> set, which will keep whitespace in your output. You can add <xsl:strip-space elements="*"> to tell it to where to delete whitespace.