Вот так заработало)
<!DOCTYPE html>
<html>
<head>
<title>Селекты</title>
<meta charset="utf-8">
</head>
<script type="text/javascript">
function calculat (obj) {
var select = document.querySelector('#r1');
var val = [{a : 10},{a : 2},{a : 1}][select.value];
var q = val.a;
obj.res1.value= q;
var m = document.getElementById("r2");
var s = m.value;
obj.res2.value= s;
}
</script>
<form >
<select id="r1" >
<option value="0"selected>1</option>
<option value="1">2</option>
<option value="2">3</option>
</select>
<input type="text" style="width:55px" id="res1"><br>
<select id="r2">
<option value="14">4</option>
<option value="15">5</option>
<option value="16">6</option>
</select>
<input type="text" style="width:55px" id="res2">
<input type="button" name="WB" value="Ok" onclick="calculat(form)">
</form>
</html>