<script>
function test()
{
document.form1.b.value=document.form1.a.options[document.form1.a.selectedIndex].text;
alert(document.form1.b.value)
}
</script>
<form name=form1>
<select name="a" id="a" onchange="test();">
<option value="F" selected>发货</option>
<option value="C">出差</option>
</select>
<input type=hidden name=b>
</form>