Is there a simple javascript snippet that can achieve this effect?

I have the following code that is being dynamically generated by joomla:

HTML Code:
<div class="cbUserListFieldLine"><span class="cbUserListFieldTitle cbUserListFT_cb_extdesc">Specialty:</span> <span class="cbListFieldCont cbUserListFC_cb_extdesc"> </span></div>
Is there a snippet of javascript that could specify to make the div with class "cbUserListFieldLine" invisible if the span with class "cbUserListFC_cb_extdesc" is empty?

Sorry, I'm still very new to hand coding javascript and don't even know where to start with making it do what I want it to. Even a general direction would be helpful.