Lazy Load Images Only After Bootstrap Modal has Opened

Question

I found two similar answers here but both were unsuccessful for my situation (given my limited ability to translate them to my situation). I have a page with a lot of fairly large images and the default method of Bootstrap is to load all the modal images upon page load. The visible html renders fairly quickly (I have a spinner for that) but the additional load time for the hidden modals makes the page impractical. I want the page to load only the visible (non-modal) content to complete the page load (and clear the spinner) and then load each modal's content only when that modal is fired. I've tried every lazyload solution I could find but the images will not render in the modal (the 'data-src' placeholders render but not the 'src' images that are supposed to replace them). I only want to lazyload (or load on 'show.bs.modal') the large images of the modal, those within the 'modal-body' class. I hope this is clear enough.

Sample code:

/* Javascript placed in the head */

<script>

function lazyLoad(){
    var $images = $('.lazy_load');

    $images.each(function(){
        var $img = $(this),
            src = $img.attr('data-src');

        $img
            .on('load',imgLoaded($img[0]))
            .attr('src',src);
        });
    };

    $('.modal-body').on("show.bs.modal", function () {
    lazyLoad();
};          

</script>

/* HTML in the modal section */


<div class="portfolio-modal modal fade" id="portfolioModal1" tabindex="-1" role="dialog" aria-hidden="true">
        <div class="modal-content">
            <div class="galleryheader">
                <img src="headerimage_1.png" height="77" width="1024">
            </div>
            <div class="close-modal" data-dismiss="modal">
                <div class="lr">
                    <div class="rl">
                    </div>
                </div>
            </div>
            <div class="container">
                <div class="row">
                    <div>
                        <div class="modal-body lazy_load">
                            <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-src="images/largeimage_1A.jpg" height="585" width="800"class="img-centered" alt=""/>
                        </div>
                        <div class="modal-body lazy_load">
                            <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-src="images/largeimage_1A.jpg" height="585" width="800"class="img-centered" alt=""/>
                        </div>
                        <div class="modal-body lazy_load">
                            <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-src="images/largeimage_1A.jpg" height="585" width="800"class="img-centered" alt=""/>
                        </div>
                    </div>
                </div>
            </div>

                <div class="close-lower" data-dismiss="modal">
                <IMG SRC="images/close.jpg" WIDTH="85" HEIGHT="32"></a>
                </div>
            </div>
        </div>
</div>

Answer 1

Firstly, put the lazy_load class on the img element, not on the parent div. Secondly the jQuery you need is something like this:

$('.portfolio-modal').on("show.bs.modal", function () {
    $('.lazy_load').each(function(){
        var img = $(this);
        img.attr('src', img.data('src'));
    });
});          

Notes:

1. Use the portfolio-modal class to identify the modal.
2. Use the jQuery data() method to get the image to lazily load.