Lazy Loading in Flexslider

Question

I am trying to get lazy loading working for Flexslider by using Lazy Loading jquery plugin and following the instructions on this site: http://www.appelsiini.net/projects/la

Answer 1

I am trying to do the same thing using Flexslider 2 and the Lazy Load Plugin for jQuery.

It seems the container property only works if the element is styled with overflow:scroll;

I was able to get the lazy load to work using this code:

$("#flexcontainer img.lazy").lazyload({
    failure_limit : 10,
    effect: "fadeIn",
    skip_invisible : false
});

However, this just lazy loads everything at once instead of as the flexslider animates.

I was also able to get it to work on mouse over using this code:

 $("#flexcontainer img.lazy").lazyload({
     failure_limit : 10,
     effect: "fadeIn",
     event : "mouseover"
 });

However this doesn't work on touch devices.

I think the key is to create your own custom event and have it trigger after a flexslider callback such as the after callback.

Answer 2

So I added the real image page to the data-attr attribute on the image tag and on after event fire I would find the image with active class and set the img src attribute equal to data-attr value.

Answer 3

You might as well initialize lazyload with a custom trigger event ...

$jQ("img[data-original]").lazyload({
            effect: "fadeIn",
            skip_invisible: false,
            event: "forceLazyLoad"
        });

... and then call this event to preload all your images inside the flexslider with a call like:

$jQ('.flex-viewport').find('img[data-original]').trigger('forceLazyLoad');

Answer 4

For the sake of offering an alternative solution - another option is to use a responsive slider which already has lazy load built into it, for example royal slider, here is the link -> http://dimsemenov.com/plugins/royal-slider/

Answer 5

I implemented a lazy load during scrolling. This solution works better for big collections in comparison with other solutions proposed here. During initialization it loads only first 5 images and then it loads ahead 3 images for every animation.

<li>
  <img class="lazy" src="loading-image.jpg" data-src="actual-image.jpg" />
</li> 

and javascript code:

    $('.flexslider').flexslider({
        animation: "slide",
        animationLoop: false,
        controlNav: false,
        init: function (slider) {
            // lazy load
            $("img.lazy").slice(0,5).each(function () {
                var src = $(this).attr("data-src");
                $(this).attr("src", src).removeAttr("data-src").removeClass("lazy");
            });
        },
        before: function (slider) {
            // lazy load
            $("img.lazy").slice(0,3).each(function () {
                var src = $(this).attr("data-src");
                $(this).attr("src", src).removeAttr("data-src").removeClass("lazy");
            });
        }
    });

Answer 6

The method works pretty well for me, but the loading image does need to be the same size as the rest of the images. I actually use http://imageresizing.net/ with mode=pad

In the main container that you are using for flexslider, put the actual image in a "data-src" attribute

<li>
  <img class="lazy" src="loading-image.jpg" data-src="actual-image.jpg" />
</li>            

In you initialization function, use the "start" callback to replace the loading image with the actual image, and remove the attribute

$('#slider').flexslider({
    start: function (slider) {
       // lazy load
       $(slider).find("img.lazy").each(function () {
          var src = $(this).attr("data-src");
          $(this).attr("src", src).removeAttr("data-src");
       });
     }
});

I hope this helps someone.