Following are my frames:

<frameset cols="600,*">
<frame name="a" src="a.html">
<frameset rows="300,*">
<frame name="b" src="b.html">
<frame name="c" src="c.html">

The content of c.html:
<p> Price <span id="price">0</span> </p>

The content of b.html:
<button type="button" onclick="myfunc()"></button>

Now, in the javascript myfunc() function, I want to use innerHTML on <span> element of file c.html. How can I access the id of the span element?

Thanks a lot for any help.