jQuery:如果ul为空 [英] jquery: if ul is empty

问题描述

好吧，我有一个jQuery对话框，其中包含一个表单，我不知所措，试图弄清楚这一点...让我们看看我是否可以口头表达我要做的事情.

Okay I have a jQuery dialog box which has a form in it and I am at my wits end trying to figure this out... Lets see if I can verbalize what I am trying to do..

我有3个文本框. #apInterest，#apPayment和#apPrincipal的确切顺序.

I have 3 text boxes. #apInterest, #apPayment and #apPrincipal in that exact order.

我要做什么的基本英语术语:

basic english terms of what i am trying to do:

在keyup上触发错误..否则检查ul#mylist是否具有任何li，如果没有.hide

on keyup in #apInterest if .val is less than 0 or greater than 99.99 trigger an error.. else check ul#mylist if it has any li, if not .hide

触发错误，否则请检查li隐藏的列表.

on keyup in #apPayment if .val is less than 0 trigger an error else check the list for li hide if not.

#apPrincipal与#apPayment

我现在正确的是什么

$('#apInterest').live("keyup", function(e) {
var parent = $('.inter').parents("ul:first");
if ($('#apInterest').val() < 0 || $('#apInterest').val() > 99.99) {
    $('.inter').remove();
    $('#mylist').append('<li class="inter">Interest Rate cannot be below 0 or above 99.99</li>');
    $('#popuperrors').show();
    $(this).addClass('error');
} else {
    $(this).removeClass('error');
    $('.inter').remove();
    alert(parent.children().text);
    if (parent.children().length == 0){
        $('#popuperrors').hide();
    }
}
});

尽管我也尝试过

if ($("#mylist :not(:contains(li))") ){
$('#popuperrors').hide();
}

对于所有3个文本框，我都具有与此功能相似的功能，但我尝试过的所有功能似乎均无效..关于如何完成此操作的任何想法

I had a function similar to this for all 3 textboxes but none of what I have tried seems to work.. any ideas on how to complete this

推荐答案

if ($('#mylist li').length == 0) ...

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