Javascript 我如何计算使用 jQuery 在页面上选择了多少个复选框
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How do I count how many checkboxes are selected on a page with jQuery
提问by Vivian River
I want to count how many checkboxes on my page are selected using jQuery. I've written the following code:
我想计算我的页面上使用 jQuery 选择了多少个复选框。我编写了以下代码：
var numberOfCheckboxesSelected = 0;
$(':checkbox').each(function(checkbox) {
if (checkbox.attr('checked'))
numberOfCheckboxesSelected++;
});
However, my code errors out with the message "Object doesn't support this property or method" on the third line.
但是，我的代码在第三行出现错误消息“对象不支持此属性或方法”。
How do I count how many checkboxes are selected on my page?
如何计算我的页面上选中了多少个复选框？
回答by Stephen
jQuery supports the :checkedpseudo-selector.
jQuery 支持:checked伪选择器。
var n = $("input:checked").length;
This will work for radio buttons as well as checkboxes. If you just want checkboxes, but also have radio buttons on the page:
这适用于单选按钮和复选框。如果您只想要复选框，而且页面上还有单选按钮：
var n = $("input:checkbox:checked").length;
回答by Chandu
Try this(to avoid counting any selected radio buttons):
试试这个（以避免计算任何选定的单选按钮）：
var numberOfCheckboxesSelected = $('input[type=checkbox]:checked').length;
回答by lonesomeday
The first argument passed to the callback in eachis the index, not the element. You should use thisor a second argument:
传递给回调的第一个参数each是索引，而不是元素。您应该使用this或第二个参数：
$(':checkbox').each(function(idx, checkbox) {
if (checkbox.attr('checked'))
numberOfCheckboxesSelected++;
});
Moreover, the easier way to do this is to select only the checked elements with the :checkedselector and then check the selection's lengthproperty:
此外，更简单的方法是使用选择器只选择选中的元素，:checked然后检查选择的length属性：
var numberOfCheckboxesSelected = $('input:checkbox:checked').length;
回答by derek
$("input:checked").length
this will return the count of checked checkboxes.
这将返回选中复选框的计数。
