const uploadInput = document.body.appendChild(

  Object.assign(document.createElement('input'), {

    type: 'file',

    accept: 'image/png, image/jpeg'

  })

);

const imageEl = document.body.appendChild(

  Object.assign(document.createElement('img'), {

    style: `

            display:block;

            width: 100%;

          `

  })

);

const reader = new FileReader();

reader.addEventListener('load', () => {

  imageEl.src = reader.result;

});

uploadInput.addEventListener('change', e => {

  const file = e.target.files[0];

  if (file != null) {

    reader.readAsDataURL(file);

  }

});