Reset 2nd select

I need to reset the 2nd select named "sty" to "selected" when the first one named "let" is onchanged.
I'm close but need this kinda quickly. Thanks fellers

<form name="sara">

<select name="let" onchange="">
<option selected>Desert</option>
<option>Ocean</option>
<option>Sky</option>
</select>

<select name="sty">
<option selected>Black</option>
<option>Green</option>
<option>Blue</option>
</select>

</form>

function resetOption(){
document.sara.sty.selectedIndex = 0;
}

Ahh...Thanks Kor...I was thinking defaultValue. :D