title: DropZone.js: How to disable file Uploading and only allow adding to dropzone via drag and drop
body: <p>In <code>dropzone</code> (or <code>vue2dropzone</code>), is there a way to <strong>disable file uploading</strong> and only **allow adding to dropzone via <em>drag and drop</em>.</p>
  
  <p>I've a setup where I successfully setup a drag and drop to child Zones (clickable: <code>.czs1</code>,) in a dropzone using a custom preview Template  as shown by AlexanderYW <a href="https://github.com/rowanwins/vue-dropzone/issues/203#issuecomment-337033660" rel="nofollow noreferrer">here</a> in this issue <a href="https://github.com/rowanwins/vue-dropzone/issues/203" rel="nofollow noreferrer">How to properly add files manually?</a>.</p>
  
  <p>DropZone Options:</p>
  
  <pre><code>dropzoneOptions: {
      url: 'http://localhost:3000/imageUpload',
      thumbnailWidth: 250,
      autoProcessQueue: false,
      addRemoveLinks: true,
      clickable: `.czs1`,
      previewTemplate: this.template(),
    },
  </code></pre>
  
  <p><strong>Now</strong> all I want to do is to disable childZones from <em>triggering OS file Upload dialog box</em> when clicked.  I found that dropzone has the input tag hidden with a class <code>dz-hidden-input</code></p>
  
  <p><code>&lt;input type="file" class="dz-hidden-input" style="visibility: hidden; position: absolute; top: 0px; left: 0px; height: 0px; width: 0px;"&gt;</code></p>
  
  <p>so in the following, I get hold of inputs with <code>.dz-hidden-input</code> className and then <code>event.preventDefault()</code> for each however that does not work.</p>
  
  <pre><code>  var dropZoneInput = document.getElementsByClassName('dz-hidden-input')
  
    dropZoneInput.forEach(item =&gt; {
         item.addEventListener('click', function () {
             event.preventDefault()
         })
    })
  
  </code></pre>
  
  <p>Is there a to achieve this in a standard API (provided by Dropzone). If not how this can be solved because the above <code>document.getElementsByClassName('dz-hidden-input')</code> does not work.</p>
  
  <p>Thanks.</p>