Unit 3 — Advanced Internet Technologies

Lesson 11 — Introduction to XSL

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Objectives

Create simple XML/XSL Web Pages. Understand what an Xpath is and how to use

it. Use the <xsl:value-of> tag to extract and

display XML data. Use the <xsl:attribute> tag to make Web

content dynamic.

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Objectives (cont.)

Use the <xsl:for-each> tag to display XML data repetitively.

Use the <xsl:if> tag for conditional XML data processing.

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XSL Basics

XSL stands for XML Stylesheet Language. XSL was designed to be a companion

technology to XML.

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Hello World—Again

XSL documents are called stylesheets. The purpose of XSL stylesheets is to define

how XML data should be displayed in a Web browser.

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Hello World—Again (cont.)

The XSL stylesheet for a particular XML document is identified by an XML directive tag.

<?xml-stylesheet type=“text/xsl” href=“[URL]”?>

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Hello World—Again (cont.)

All XSL stylesheets must include an <xsl:stylesheet> tag and an <xsl:template> tag.

The <xsl:stylesheet> tag identifies the XML namespace to use.

The <xsl:template> tag identifies the root node of the corresponding XML document.

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XSL Transformations

Combining an XML document with an XSL stylesheet is called transforming it.

The resulting Web page is called an XML Stylesheet Language Transformation (XSLT).

The <xsl:value-of> tag extracts a data value from an XML file and displays it.

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Understanding Xpaths

An Xpath is a notational convention used to identify a particular data element in an XML document.

Xpaths can be absolute or relative.

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Text Strings in XSL

Placing arbitrary text strings in XSL stylesheets can cause syntax errors.

Static text strings should be enclosed within <xsl:text> and </xsl:text> tags.

<xsl:text>Hello XSL World!</xsl:text>

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XSL Tag Attributes

Static XSL tag attributes must follow the same syntax rules as XML and XHTML tag attributes.

XSL allows tag attributes to be added dynamically with the <xsl:attribute> tag.

Dynamic attribute values can be extracted and set with the <xsl:value-of> tag.

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XSL Conditional Tags

All programming languages include “if” statements.

XSL supports conditional processing with the <xsl:if> tag.

The condition is specified in the test attribute of the <xsl:if> tag.

<xsl:if> tags can determine whether a particular XML data element is present or not.

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Summary

You created simple XML/XSL Web pages. You understand what an Xpath is and how to

use it. You used the <xsl:value-of> tag to extract and

display XML data. You used the <xsl:attribute> tag to make Web

content dynamic.

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Summary (cont.)

You used the <xsl:for-each> tag to display XML data repetitively.

You used the <xsl:if> tag for conditional XML data processing.