[jQuery] Validate a Children

[jQuery] Validate a Children

Hi
 I have two markups
<div id="markup1"...
<div id="markup2"...
If markup1 dont have childrens and markup2 have childrens so
$("#markup1").append($("#markup2").children().get(1)).show();
How can I write the first statement?<br clear="all">
Regards
macm