<script language=javascript>
function select1_onchange(){
if (select1.value=="B"){
select2.value="2";
}
}
</script><select name=select1 onchange="select1_onchange()">
<option value=A>A</option>
<option value=B>B</option>
<option value=C>C</option>
</select><select name=select2>
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
</select>
function select1_onchange(){
if (select1.value=="B"){
select2.value="2";
}
}
</script><select name=select1 onchange="select1_onchange()">
<option value=A>A</option>
<option value=B>B</option>
<option value=C>C</option>
</select><select name=select2>
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
</select>
<form name=temp>
<select name=select1 onchange=javascript:document.temp.select2.value='2'>
<option value=A>A</option>
<option value=B>B</option>
<option value=C>C</option>
</select><select name=select2>
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
</select>
</form>
<select name=select1 onchange=javascript:select2.selectedIndex=this.selectedIndex>
<option value=A>A</option>
<option value=B>B</option>
<option value=C>C</option>
</select><select name=select2>
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
</select>
</form>