JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://rawgithub.com/jquery/jquery-ui/master/ui/jquery.ui.widget.js"></script>
<script src="http://rawgithub.com/blueimp/jQuery-File-Upload/master/js/jquery.fileupload.js"></script>
<script src="http://fiddle.jshell.net/js/lib/mootools-core-1.4.5-compat.js"></script>
<form action="/echo/json/" method="POST">
    <input name="file1[]" type="file" multiple />
    <br />
    <input name="file2[]" type="file" multiple />
    <br />
    <input name="file3[]" type="file" multiple />
    <br />
    <button type="button">send by fileupload send api</button>
</form>

JavaScript

$(document).ready(function () {
    var filesList = []
    var elem = $("form")
    file_upload = elem.fileupload({
        autoUpload: false,
        fileInput: $("input:file"),
    }).on("fileuploadadd", function (e, data) {
        filesList.push(data.files[0])
    });;

    $("button").click(function () {
        file_upload.fileupload('send', {
            files: filesList,
            formData: {
                json: JSON.encode({
                    extra: 1
                })
            }
        })
    })
})