question about child::node()

[abbouh <ab...@ra...>]

what is the difference between:
<xsl:if test="local-name(//preface/child::paramod)"/>
and
<xsl:if test="local-name(//preface/child::node())='paramod'">

the first test works but the second not why?

i want to test if the child of the node "prefcae"  is "paramod" node.