first find child div postion top and set to span id box postion margin-top.
here the code
<div id="parent" style="border:2px solid black">
<div id="child">
</div>
</div>
This is my jquery code:
$("#child").after("<span id="child1"><p> large text data</p> </span>");
var p = $("#child");
var position = p.position();
$("#child1").css("margin-top",position.top+"px");
its with out using position absolute.it's working fine.height problem fixed.