javascript - 获取总和当前幻灯片编号引导滑块
问题描述
通过 JavaScript 和引导控件了解幻灯片数量的最简单方法。按下按钮时,计数器递增或递减,标准引导轮播和带有 .num 类的 .num 类来显示总数和当前数量,我使用了这段代码检索数字,但没有通过
var totalItems = $('.item').length;
var currentIndex = $('div.item.active').index() + 1;
var down_index;
$('.num').html(''+currentIndex+'/'+totalItems+'');
$(".next").click(function(){
currentIndex_active = $('div.item.active').index() + 2;
if (totalItems >= currentIndex_active)
{
down_index= $('div.item.active').index() + 2;
$('.num').html(''+currentIndex_active+'/'+totalItems+'');
}
});
$(".prev").click(function(){
down_index=down_index-1;
if (down_index >= 1 )
{
$('.num').html(''+down_index+'/'+totalItems+'');
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<div class="num"></div>
<div id="carouselExampleIndicators" class="carousel slide" data-ride="carousel" data-wrap="false" data-interval="false">
<div class="carousel-inner">
<div class="carousel-item item active">
<img class="d-block w-100" src="https://via.placeholder.com/500x300" alt="First slide">
</div>
<div class="carousel-item item">
<img class="d-block w-100" src="https://via.placeholder.com/500x300" alt="Second slide">
</div>
<div class="carousel-item item">
<img class="d-block w-100" src="https://via.placeholder.com/500x300" alt="Third slide">
</div>
</div>
<a class="carousel-control-prev prev" href="#carouselExampleIndicators" role="button" data-slide="prev">
<span class="carousel-control-prev-icon" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="carousel-control-next next" href="#carouselExampleIndicators" role="button" data-slide="next">
<span class="carousel-control-next-icon" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
解决方案
正确的 jQuery 选择器将.carousel-item
代替.item
...
var totalItems = $('.carousel-item').length;
var currentIndex = $('.carousel-item.active').index() + 1;
var down_index;
$('.num').html(''+currentIndex+'/'+totalItems+'');
$(".next").click(function(){
currentIndex_active = $('.carousel-item.active').index() + 2;
if (totalItems >= currentIndex_active)
{
down_index= $('.carousel-item.active').index() + 2;
$('.num').html(''+currentIndex_active+'/'+totalItems+'');
}
});
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