Usage no npm install needed!

<script type="module">
  import dothiswhenvisible from 'https://cdn.skypack.dev/dothiswhenvisible';
</script>

README

doThisWhenVisible

A small jQuery plugin to execute a callback when an element is above the bottom of the viewport.

doThisWhenVisible is a jQuery plugin, so make sure you have jQuery on the page before you include this.

<script src="//code.jquery.com/jquery-2.2.4.min.js"></script>
<script src="path/dist/jquery.dothiswhenvisible.min.js"></script>

Then you just need to get a hold of the element(s) you want to monitor and call doThisWhenVisible, passing in your callback.

jQuery('.target').doThisWhenVisible(function($el){
    console.log('It would appear that ', $el, ' is now visible');
});