DropzoneJS is an open source library that provides drag’n’drop file uploads with image previews. It’s lightweight and works without any other library (like jQuery). It’s highly customizable and easy to use.
The basic example of use
<link rel="stylesheet" href="dropzone.css">
This is the most minimal example. Drop your file...
<!-- change it to your upload address -->
<form action="/upload.php" class="dropzone"></form>
We only need upload.php script (PHP or any other back-end technology) to handle uploaded file on the server.