How to make use of it:

Load the minified model of the defer.js library within the doc.

<script src="defer.min.js"></script>

Defer the loading of JavaScript inside the doc. In this instance, the goal script will look forward to 3 seconds to load after the web page is absolutely loaded.

// deferscript(src, id, delay, callback)
deferscript('target.js', 'target-id', 2000, function() {
  // do something
});

Defer the loading of CSS inside the doc.

// deferstyle(src, id, delay)
deferstyle('target.css', 'target-id', 2000);

Lazy load photographs inside the doc.

<img class="demo"
     data-src="target.jpg">

deferimg('demo', 100, 'loaded', function(img) {
  img.onload = function() {
    img.classList.add('show');
  }
});

Lazy load iframes inside the doc. Ideal for Youtube & Vimeo videos.

<iframe class="video"
        data-src="https://www.youtube.com/embed/VIDEO-ID"
>
</iframe>

deferiframe('video', 100, 'loaded', function(frame) {
  frame.onload = function() {
    frame.classList.add('show');
  }
});

Delay The Loading Of Anything, defer.js Plugin/Github

See Demo And Download