form.pug

doctype html
html(lang="en")
  head
    title Static Files
    meta(charset='utf-8')
    link(rel="stylesheet", href="/static/main.css")
  body
    form(method="POST", action="/upload", enctype="multipart/form-data")
      input(type="file", name="file")        
      input(type="submit")
    img(id="output", alt='None to show :(')
  script.
    var loadFile = function(event) {
        var image = document.getElementById('output');
        image.src = URL.createObjectURL(event.target.files[0]);
    };