Filer is jQuery plugin for custom file upload inputs.
To use it just add the styles and the javascript into your project.
<link rel="stylesheet" href="jquery.filer.css" type="text/css" media="all" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="jquery.filer.js"></script>
To init the plugin add this:
<script>
$('input[type="file"]').filer();
</script>