Javascript code to use Flexslider to change a background image after each slide change.

Flexslider to Change Background Image

$(document).ready(function() {
    var imgArr = new Array (
        <?php 
        $total = count(get_field('field'));
        $count = 1;
        while(the_repeater_field('field', $pagenumber)): ?>
            '<?php the_sub_field('sub_field'); ?>'<?php if($count < $total){echo ',';} $count++; ?>
        <?php endwhile; ?>
    );
    var n = 0;
    function preload(arrayOfImages) {
        $(arrayOfImages).each(function(){
            $('<img/>')[0].src = this;
        });
    }
    preload(imgArr);
    $('.flexslider').flexslider({
        start: function(slider) {
            $('#container').attr('style', 'background-image: url(' + imgArr[n] + '); background-position: center; background-repeat: no repeat; background-size: cover;');
        },
        before: function(slider) {
        },
        after: function(slider) {
            n = slider.currentSlide;
            $('#container').attr('style', 'background-image: url(' + imgArr[n] + '); background-position: center; background-repeat: no repeat; background-size: cover;');
        }
    });
});

I have also tried to implement this, but I have not found it working. then I have replaced the img tag with the following

<div style="background-image: url('.$slide['url'].'); background-repeat: no repeat; background-size: cover;height:100%; width:100%;" ></div>

It worked very well without distorting the image in background. but for it, you have to set the height of

tag(Parent of div) and we don't need to implement flex slider "start, before, after" callback.