RE: Which commands to use: xsl:if, xsl:when, xsl:choose, xsl:otherwis

(Simple english language explanation)

If you only want if (no else) use if.
When you need else, use when for if, otherwise for else.
Choose is required to contain a list of whens, and optionally one otherwise.

(humorously yours)

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list