可能重复:检查特定单选按钮

我现在有这两个单选按钮，以便用户可以决定他们是否需要在价格中包含邮资:

I have these 2 radio buttons at the moment so that the user can decide whether they need postage included in the price or not:

<input type="radio" id="postageyes" name="postage" value="Yes" /> Yes
<input type="radio" id="postageno" name="postage" value="No" /> No

我需要使用 Jquery 来检查是否选中了是"单选按钮，如果是，请执行附加功能.有人可以告诉我该怎么做吗?

I need to use Jquery to check if the 'yes' radio button is checked, and if it is, do an append function. Could someone tell me how I'd do this please?

感谢您的帮助

我已将我的代码更新为此，但它不起作用.我做错了吗?

I've updated my code to this, but it's not working. Am I doing something wrong?

<script type='text/javascript'>
// <![CDATA[
jQuery(document).ready(function(){

$('input:radio[name="postage"]').change(function(){
    if($(this).val() == 'Yes'){
       alert("test");
    }
});

});

// ]]>
</script>

推荐答案

$('input:radio[name="postage"]').change(
    function(){
        if ($(this).is(':checked') && $(this).val() == 'Yes') {
            // append goes here
        }
    });

或者，以上 - 再次 - 使用一点 less 多余的 jQuery:

Or, the above - again - using a little less superfluous jQuery:

$('input:radio[name="postage"]').change(
    function(){
        if (this.checked && this.value == 'Yes') {
            // note that, as per comments, the 'changed'
            // <input> will *always* be checked, as the change
            // event only fires on checking an <input>, not
            // on un-checking it.
            // append goes here
        }
    });

修改(改进了一些)jQuery:

Revised (improved-some) jQuery:

// defines a div element with the text "You're appendin'!"
// assigns that div to the variable 'appended'
var appended = $('<div />').text("You're appendin'!");

// assigns the 'id' of "appended" to the 'appended' element
appended.id = 'appended';

// 1. selects '<input type="radio" />' elements with the 'name' attribute of 'postage'
// 2. assigns the onChange/onchange event handler
$('input:radio[name="postage"]').change(
    function(){

        // checks that the clicked radio button is the one of value 'Yes'
        // the value of the element is the one that's checked (as noted by @shef in comments)
        if ($(this).val() == 'Yes') {

            // appends the 'appended' element to the 'body' tag
            $(appended).appendTo('body');
        }
        else {

            // if it's the 'No' button removes the 'appended' element.
            $(appended).remove();
        }
    });

var appended = $('<div />').text("You're appendin'!");
appended.id = 'appended';
$('input:radio[name="postage"]').change(function() {
  if ($(this).val() == 'Yes') {
    $(appended).appendTo('body');
  } else {
    $(appended).remove();
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"></script>
<input type="radio" id="postageyes" name="postage" value="Yes" />Yes
<input type="radio" id="postageno" name="postage" value="No" />No

JS Fiddle 演示.

此外，还有一个温和的更新(因为我正在编辑以包含片段以及 JS Fiddle 链接)，以便用 包装