Jquery如果选中单选按钮 [英] Jquery If radio button is checked

问题描述

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 元素<label>s - 允许单击文本以更新相关 <input/> - 并更改创建要附加的内容的方式:

And, further, a mild update (since I was editing to include Snippets as well as the JS Fiddle links), in order to wrap the <input /> elements with <label>s - allow for clicking the text to update the relevant <input /> - and changing the means of creating the content to append:

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

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label>
  <input type="radio" id="postageyes" name="postage" value="Yes" />Yes</label>
<label>
  <input type="radio" id="postageno" name="postage" value="No" />No</label>

JS Fiddle 演示.

此外，如果您只需要根据用户检查的元素来显示内容，则可以稍微更新一下，使用显式显示/隐藏来切换可见性:

Also, if you only need to show content depending on which element is checked by the user, a slight update that will toggle visibility using an explicit show/hide:

// caching a reference to the dependant/conditional content:
var conditionalContent = $('#conditional'),
    // caching a reference to the group of inputs, since we're using that
    // same group twice:
    group = $('input[type=radio][name=postage]');

// binding the change event-handler:
group.change(function() {
  // toggling the visibility of the conditionalContent, which will
  // be shown if the assessment returns true and hidden otherwise:
  conditionalContent.toggle(group.filter(':checked').val() === 'Yes');
  // triggering the change event on the group, to appropriately show/hide
  // the conditionalContent on page-load/DOM-ready:
}).change();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label>
  <input type="radio" id="postageyes" name="postage" value="Yes" />Yes</label>
<label>
  <input type="radio" id="postageno" name="postage" value="No" />No</label>
<div id="conditional">
  <p>This should only show when the 'Yes' radio &lt;input&gt; element is checked.</p>
</div>

最后，只使用 CSS:

And, finally, using just CSS:

/* setting the default of the conditionally-displayed content
to hidden: */
#conditional {
  display: none;
}

/* if the #postageyes element is checked then the general sibling of
that element, with the id of 'conditional', will be shown: */
#postageyes:checked ~ #conditional {
  display: block;
}

<!-- note that the <input> elements are now not wrapped in the <label> elements,
in order that the #conditional element is a (subsequent) sibling of the radio
<input> elements: -->
<input type="radio" id="postageyes" name="postage" value="Yes" />
<label for="postageyes">Yes</label>
<input type="radio" id="postageno" name="postage" value="No" />
<label for="postageno">No</label>
<div id="conditional">
  <p>This should only show when the 'Yes' radio &lt;input&gt; element is checked.</p>
</div>

JS Fiddle 演示.

参考资料:

• CSS:
  • :checked 选择器.
  • CSS 属性选择器.
  • 通用兄弟 (~) 组合子.
  • appendTo().
  • attribute-equals 选择器.
  • change().
  • :checked 选择器.
  • filter().
  • is().
  • :radio 选择器.
  • remove().
  • text().
  • toggle().
  • val().

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