xsl:choose

<xsl:choose>
Syntax:

<xsl:choose> <xsl:when test=”expression”>

</xsl:when>
… <xsl:otherwise>

</xsl:otherwise>
</xsl:choose>

The xsl:choose element is used to make a choice when there are two or more possible courses of action. It provides a means for conducting multiple conditions testing.
The xsl:choose element must contain one or more xsl:when elements and can contain only one optional xsl:otherwise element (which must occur after all of the xsl:when elements). If the xsl:chooseelement only contains one xsl:when element, then for all practical purposes, it behaves just like the xsl:if element.
When faced with three or more choices, this element behaves like an if-then-else statement (or a Select Case) as found in numerous other computer languages.
Each xsl:when element is examined in the order of occurrence. If and when the conditions of the test expression are satisfied (returns True), the code contained in that element is executed.
Then the xsl:choose element is automatically exited and all further xsl:when elements are ignored and are not tested. The optional xsl:otherwise element is also automatically ignored.
If none of the test conditions in any xsl:when element is satisfied (all return False), then the xsl:otherwise element is automatically selected (if it is present) and the code associated with that element is executed. If there is no xsl:otherwise element, then the xsl:choose element is exited.
This element has no attributes. It is not a self-closing tag. The separate closing element is mandatory.