rails4：多个图片上传

Question

我正在尝试使用carrierwave上传多个图像，当我一次选择多个图像（shift + select）时一切正常，但在我的情况下，我也有兴趣逐项上传文件以显示它们缩略图。

问题是当我一次选择一张图片时，在提交表格后只会上传最后一张图片

 <%= f.fields_for :product_attachment do |p| %>
  <div class="field" id="uploads-form">
    <%= p.label :image %><br>
    <%= p.file_field :image,multiple:true,name:"product_attachments[image][]",id:"files"%>
 <output id="list"></output>
  </div>

<% end %>

剧本：

<script>
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object

// Loop through the FileList and render image files as thumbnails.
for (var i = 0, f; f = files[i]; i++) {

  // Only process image files.
  if (!f.type.match('image.*')) {
    continue;
  }

  var reader = new FileReader();

  // Closure to capture the file information.
  reader.onload = (function(theFile) {
    return function(e) {
      // Render thumbnail.
      var span = document.createElement('span');
      span.innerHTML = ['<img class="thumb" src="', e.target.result,
                        '" title="', escape(theFile.name), '"/>'].join('');
      document.getElementById('list').insertBefore(span, null);
    };
  })(f);

  // Read in the image file as a data URL.
  reader.readAsDataURL(f);
}
 }

document.getElementById('files').addEventListener('change', handleFileSelect, false);