1function previewImages() {
2
3  var preview = document.querySelector('#preview');
4  
5  if (this.files) {
6    [].forEach.call(this.files, readAndPreview);
7  }
8
9  function readAndPreview(file) {
10
11    // Make sure `file.name` matches our extensions criteria
12    if (!/\.(jpe?g|png|gif)$/i.test(file.name)) {
13      return alert(file.name + " is not an image");
14    } // else...
15    
16    var reader = new FileReader();
17    
18    reader.addEventListener("load", function() {
19      var image = new Image();
20      image.height = 100;
21      image.title  = file.name;
22      image.src    = this.result;
23      preview.appendChild(image);
24    });
25    
26    reader.readAsDataURL(file);
27    
28  }
29
30}
31
32document.querySelector('#file-input').addEventListener("change", previewImages);

1<input id="file-input" type="file" multiple>
2<div id="preview"></div>