<html lang="en-US">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>Styled file picker example</title>
    <link href="https://fonts.googleapis.com/css?family=Josefin+Sans&display=swap" rel="stylesheet">
  </head>

  <body>
    <form>
      <div>
        <label for="file">Choose a file to upload</label>
        <input id="file" name="file" type="file" multiple>
        <ul id="file-list"></ul>
      </div>
      <div><button>Submit?</button></div>
    </form>
  </body>
</html>
body {
  font-family: 'Josefin Sans', sans-serif;
  margin: 20px auto;
  max-width: 400px;
}

form > div {
  margin-bottom: 20px;
}

button, label, input {
  display: block;
  font-family: inherit;
  font-size: 100%;
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  width: 100%;
  padding: 5px;
  height: 30px;
}

input[type="file"] {
  height: 0;
  padding: 0;
  opacity: 0;
}

label[for="file"] {
  box-shadow: 1px 1px 3px #ccc;
  background: linear-gradient(to bottom, #eee, #ccc);
  border: 1px solid rgb(169, 169, 169);
  border-radius: 5px;
  text-align: center;
  line-height: 1.5;
}

label[for="file"]:hover {
  background: linear-gradient(to bottom, #fff, #ddd);
}

label[for="file"]:active {
  box-shadow: inset 1px 1px 3px #ccc;
}

button {
  width: 60%;
  margin: 0 auto;
}
const fileInput = document.querySelector('#file');
const fileList = document.querySelector('#file-list');

fileInput.addEventListener('change', updateFileList);

function updateFileList() {
  while (fileList.firstChild) {
    fileList.removeChild(fileList.firstChild);
  }

  let curFiles = fileInput.files;

  if (curFiles.length !== 0) {
    for (let i = 0; i < curFiles.length; i++) {
      const listItem = document.createElement('li');
      listItem.textContent = 'File name: ' + curFiles[i].name + '; file size ' + returnFileSize(curFiles[i].size) + '.';
      fileList.appendChild(listItem);
    }
  }
}

function returnFileSize(number) {
  if (number < 1024) {
    return number + ' bytes';
  } else if (number < 1048576) {
    return (number / 1024).toFixed(1) + ' KB';
  } else {
    return (number / 1048576).toFixed(1) + ' MB';
  }
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.