JS Radio结合TEXT

<script>
function fun_a(value){
if(value === "on"){
document.getElementById('a').disabled='';
document.getElementById('b').disabled='disabled'
}
}
function fun_b(value){
if(value === "on"){
document.getElementById('b').disabled='';
document.getElementById('a').disabled='disabled';
}
}
</script>

<tr>
<td><input type="radio" name="time-type" onchange="fun_a(this.value)" checked>准确时间
<br />&nbsp;&nbsp;&nbsp;&nbsp;<input type="date" name="time_zq" id="a"/></td>
</tr>
<tr>
<td><input type="radio" name="time-type" onchange="fun_b(this.value)">模糊时间
<br />&nbsp;&nbsp;&nbsp;&nbsp;<input type="text" name="time_mh" id="b" disabled /></td>
</tr>