[jQuery] Clear selection of text on ul element

Hello,
I am trying to get/set only text of list only element text value.
But for some reason I can not select it in clear way.
List something like:
<ul>
<li id="myid"> Here text that I want to modify
<ul>
<li id="dfdf">i don't want modify this</li>
<li id="dfdf">i don't want modify this</li>
</ul>
</li>
<ul>
Any suggestion?
Thanks in advance.