如果未选中所有复选框，则警告用户 [英] warn user if all checkboxes are unchecked

问题描述

我有一个带有一系列复选框的表格.如果未选中所有复选框，我想警告用户，请点击提交".我正在使用以下代码来报告所有复选框的值:

I have a form with a series of checkboxes. I want to warn the user, after they hit submit, if ALL of the checkboxes are unchecked. I'm using the following code to report all of the values of the checkboxes:

$('[id^=leg_rider]').filter(':checked');

这似乎有效.但是，当我尝试检查返回的对象是否为空时，它似乎不起作用.这就是我正在尝试的:

This seems to work. However, when I try to check to see if the returned object is empty, it doesn't seem to work. This is what I'm trying:

        $("#set_pref_submit").click(function() {
        var legchecked = $('[id^=leg_rider]').filter(':checked');
        if (!legchecked){ alert("no riders")};
    });

任何建议都值得赞赏.谢谢！

Any suggestions are appreciated. Thanks!

推荐答案

您可以使用jQuery对象的 length 属性:

You can use jQuery object's length property:

$("#set_pref_submit").click(function() {
    var legchecked = $('input[id^=leg_rider]:checked').length;
    if (legchecked){ alert("no riders")};
});

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