Bootstrap 4 Carousel get image size

Question

Here is a very basic Bootstrap 4 Carousel with 3 images.

I implemented the 2 available events: slide.bs.carousel and slid.bs.carousel.

I am able to get the image width in the slid event listener (when the carousel has completed its slide transition) but the image width is always 0 when I try to get it in the slide listener (I want to know the size of the next slide).

Why is that?

Here is a snippet. Watch the console.

jQuery('#carouselDemo').on('slide.bs.carousel', function(e) {

  console.log('SLIDE event');
  console.log('Image width: ' + e.relatedTarget.querySelector('img').clientWidth);
});

jQuery('#carouselDemo').on('slid.bs.carousel', function(e) {

  console.log('SLID event');
  console.log('Image width: ' + e.relatedTarget.querySelector('img').clientWidth);
});

.carousel {
  background-color: grey;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>

<div id="carouselDemo" class="carousel slide" data-ride="carousel">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="https://via.placeholder.com/700x400">
    </div>
    <div class="carousel-item">
      <img src="https://via.placeholder.com/800x400">
    </div>
    <div class="carousel-item">
      <img src="https://via.placeholder.com/900x400">
    </div>
  </div>
  <a class="carousel-control-prev" href="#carouselDemo" 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" href="#carouselDemo" role="button" data-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="sr-only">Next</span>
  </a>
</div>

https://jsfiddle.net/upsidown/ruo0gt19/

Edit

I failed to mention that I need the next slide image client width, ie. the display width and not the original image width. Below is an example with larger images, forced to 100% max-width using the answer provided by @gaetanoM.

Note: I can't simply use the body or container element width as in my use case the carousel images are displayed in full-screen, with max-height 100% and therefore the width can vary and be smaller than the container width.

jQuery('#carouselDemo').on('slide.bs.carousel', function(e) {

    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    console.log('slide: Current element Width is: ' + fromelement[0].width);
    console.log('slide: Next element Width is: ' + toelement[0].width);

});

jQuery('#carouselDemo').on('slid.bs.carousel', function(e) {

    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    console.log('slid: Current element Width is: ' + fromelement[0].width);
    console.log('slid: Next element Width is: ' + toelement[0].width);
});

.carousel {
    background-color: grey;
}

.carousel-item > img {
  max-width: 100%;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>


<div id="carouselDemo" class="carousel slide" data-ride="carousel">
    <div class="carousel-inner">
        <div class="carousel-item active">
            <img src="https://via.placeholder.com/700x400">
        </div>
        <div class="carousel-item">
            <img src="https://via.placeholder.com/800x400">
        </div>
        <div class="carousel-item">
            <img src="https://via.placeholder.com/900x400">
        </div>
    </div>
    <a class="carousel-control-prev" href="#carouselDemo" 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" href="#carouselDemo" role="button" data-slide="next">
        <span class="carousel-control-next-icon" aria-hidden="true"></span>
        <span class="sr-only">Next</span>
    </a>
</div>

gaetanoM · Accepted Answer

According to the updated answer the issue is on the next/prev element when sliding (It is hidden, so there is no clientWidth).

In order to overcome this a solution can be:

toggle visibility of this hidden element
get the clientWidth
immediately re-toggle visibility in order to accomodate everyting.

In the snippet each image has a different width in order to prove the result.

jQuery('#carouselDemo').on('slide.bs.carousel', function(e) {
    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    toelement.parent().toggleClass('active');
    console.log('slide: Current element Width is: ' + fromelement[0].width + ' / ' + fromelement[0].clientWidth);
    console.log('slide: Next element Width is: ' + toelement[0].width + ' / ' + toelement[0].clientWidth);
    toelement.parent().toggleClass('active');
});
jQuery('#carouselDemo').on('slid.bs.carousel', function(e) {
    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    fromelement.parent().toggleClass('active');
    console.log('slid: Current element Width is: ' + fromelement[0].width + ' / ' + fromelement[0].clientWidth);
    console.log('slid: Next element Width is: ' + toelement[0].width + ' / ' + toelement[0].clientWidth);
    fromelement.parent().toggleClass('active');
});

.carousel {
    background-color: grey;
}

.carousel-item > img.n1 {
    width: 100%;
    height: 100vh;
}
.carousel-item > img.n2 {
    width: 50%;
    height: 100vh;
}
.carousel-item > img.n3 {
    width: 75%;
    height: 100vh;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.js"></script>


<div id="carouselDemo" class="carousel slide" data-ride="carousel">
    <div class="carousel-inner">
        <div class="carousel-item active">
            <img class="n1" src="https://via.placeholder.com/700x400">
        </div>
        <div class="carousel-item">
            <img class="n2"  src="https://via.placeholder.com/800x400">
        </div>
        <div class="carousel-item">
            <img class="n3"  src="https://via.placeholder.com/900x400">
        </div>
    </div>
    <a class="carousel-control-prev" href="#carouselDemo" 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" href="#carouselDemo" role="button" data-slide="next">
        <span class="carousel-control-next-icon" aria-hidden="true"></span>
        <span class="sr-only">Next</span>
    </a>
</div>

After reading How to get image size (height & width) using JavaScript? I would suggest to use the plain HTML img width or naturalWidth.

jQuery('#carouselDemo').on('slide.bs.carousel', function(e) {

    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    console.log('slide: Current element Width is: ' + fromelement[0].width);
    console.log('slide: Next element Width is: ' + toelement[0].width);

});

jQuery('#carouselDemo').on('slid.bs.carousel', function(e) {

    var fromelement = jQuery('#carouselDemo .carousel-inner img').eq(e.from);
    var toelement = jQuery('#carouselDemo .carousel-inner img').eq(e.to);

    console.log('slid: Current element Width is: ' + fromelement[0].width);
    console.log('slid: Next element Width is: ' + toelement[0].width);
});

.carousel {
    background-color: grey;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>


<div id="carouselDemo" class="carousel slide" data-ride="carousel">
    <div class="carousel-inner">
        <div class="carousel-item active">
            <img src="https://via.placeholder.com/700x400">
        </div>
        <div class="carousel-item">
            <img src="https://via.placeholder.com/800x400">
        </div>
        <div class="carousel-item">
            <img src="https://via.placeholder.com/900x400">
        </div>
    </div>
    <a class="carousel-control-prev" href="#carouselDemo" 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" href="#carouselDemo" role="button" data-slide="next">
        <span class="carousel-control-next-icon" aria-hidden="true"></span>
        <span class="sr-only">Next</span>
    </a>
</div>

Bootstrap 4 Carousel get image size

Tags:

javascript

html

jquery

twitter-bootstrap

bootstrap-4

Edit

MrUpsidown

1 Answers

gaetanoM

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Bootstrap 4 Carousel get image size

Tags:

javascript

html

jquery

twitter-bootstrap

bootstrap-4

Edit

MrUpsidown

1 Answers

gaetanoM

Related questions

Recent Activity

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