Click modifies another div class

[aceholleran]

I am an intermediate JSer with some success. What I want to do seems simple, but I can't grab onto it.

I want a click in "first" to modify opacity in "second"

<div class="first" onClick="i want code here to toggle opacity for class 'second'">image here</div>

<div class="second">This the div I want to change opacity in</div>

Yes, I know the proper CSS for declaring opacity. I just can't seem to find the right "call."

Any help would be muchly appreciated.

[JMRKER]

Consider this change ...

<div class="first" onClick="document.getElementById('secondID').style.opacity=xxx">image here</div>

<div id="secondID" class="second">This the div I want to change opacity in</div>