select自動送出

<form name=myform>
<select name=year_seme  onchange='jump()'>
<option value=值1>選項1</option>
<option value=值2>選項2</option>
</select>
</form>


<script language='JavaScript'>

function jump(){
  if(document.myform.year_seme.options[document.myform.year_seme.selectedIndex].value!=''){
  location="?act=&year_seme=" + document.myform.year_seme.options[document.myform.year_seme.selectedIndex].value;
}
}
</script>