const upload = new Upload({
    prefix: 'ws://127.0.0.1:8081/',
    onSendProgress: (pecent) => {
        console.log(pecent)
    }
});

document.getElementById('files').addEventListener('change', (e) => {
    console.log(this, e)
    upload.inputChange(e.target)
})

document.getElementById('btn1').addEventListener('click', (e) => {
    upload.inputUpload()
})