chooseAttribute — Selects the best value between the three paramaters.
<xsl:function name="func:chooseAttribute"> <xsl:param name="user"/> <xsl:param name="herited"/> <xsl:param name="default"/> ... </xsl:function>
This function is used to retrieve style attributes. The value specified by users has the priority and will be chosen if it is not empty. The second choice is the herited value from a parent if it is not empty. And, finally, the default one is choosen if all other values are empty.