js取select的text值

<script language="javascript">
function chk(){
   var obj = document.getElementById("sel");
   var strsel = obj.options[obj.selectedIndex].text;
   if (confirm("确定要选择"+strsel+"吗？")){

   }else{

   }
}
</script>
<select name="sel" onchange="return chk()">
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
</select>