我有2個單選按鈕,即是和否。當我選擇「是」時,文本框將被啓用。當我點擊沒有文字框被禁用。如何在點擊是時啓用文本框。這是代碼。請告訴我如何使用JavaScript啓用和禁用它。僅當單擊單選按鈕1時啓用文本框
<script type="text/javascript">
$(function() {
$("#XISubmit").click(function(){
var XIyop= document.forms["XIForm"]["XIyop"].value;
var XIForm = $('form[name=XIForm]');
var XIAlmnus = XIForm.find('input[name=XIAlmnus]:checked').val();
if (XIAlmnus == null || XIAlmnus == "")
{
alert("Please select Parent is an Alumnus (old Boy) of this school");
return false;
}
document.getElementById("XIForm").submit();
});
</script>
<!-- html code-->
<html>
...
<label>Parent is an Alumnus (old Boy) of this school </label>   
<input type='radio' name='XIAlmnus' value='Yes' id="XIyes"/>Yes
<input type='radio' name='XIAlmnus' value='No' id="XIno"/>No</td>
<label>If Yes, Year of passing </label>   
<input type="textbox" name="XIyop" id="XIyop" >
...
</html>