Question

不确定如何说出这个问题...... 我有一个脚本为每个第n个元素执行每个循环我将此作为变量：var nthCard = $('.card:nth-child(' + col + 'n+' + i + ')'); 然后我用nthCard.each(function(i){...}

做一个.each

在每次之后，我需要找出nthCards中有多少人拥有班级.featured。

html的设置如下：

<div class="card"></div>
<div class="card featured"></div>
<div class="card"></div>
<div class="card"></div>
<div class="card"></div>
<div class="card featured"></div>

假设这是每个声明，我需要找到有多少这些卡也是特色。

我尝试过这样的事情：console.log(nthCard.find('.featured').length);和console.log(nthCard.hasClass('.featured').length);，但前者返回0，后者返回undefined。

这是截断的代码：

function placeCard(col){
    var i = 0;
    for(i=1; i<= col; i++){
        var nthCard = $('.card:nth-child(' + col + 'n+' + i + ')');
        nthCard.each(function(idx){
            //do some code
        });
        console.log(nthCard.find('.featured').length);//I need to return the number of featured cards here.
    }
}

Answer 1

filter匹配的元素：

var number = nthCard.filter('.featured').length;

Answer 2

尝试：

console.log(nthCard.hasClass('featured'));

Answer 3

为什么不在每个循环中计算它们？

function placeCard(col){
    var i = 0;
    for(i=1; i<= col; i++){
        var nthCard = $('.card:nth-child(' + col + 'n+' + i + ')');
        var count = 0;
        nthCard.each(function(idx, card){
            //do some code
            if ($(card).hasClass('featured')) {
                count += 1;
            }
        });
        console.log(count);//I need to return the number of featured cards here.
    }
}

或者，更优化：

function placeCard(col){
    var i = 0;
    for(i=1; i<= col; i++){
        var nthCard = $('.card:nth-child(' + col + 'n+' + i + ')');
        var count = 0;
        nthCard.each(function(idx, card){
            //do some code
            if (card.className === 'card featured') {
                count += 1;
            }
        });
        console.log(count);//I need to return the number of featured cards here.
    }
}

jQuery按类名获取变量中的两个类之一

3 个答案: