Declarative

How to create a Dropzone upload with HTML attributes.

The easiest way to use dropzone is by creating a form element with the class dropzone:

<form action="/file-upload"
class="dropzone"
id="my-awesome-dropzone"></form>

That’s it. Dropzone will find all form elements with the class dropzone, automatically attach itself to it, and upload files dropped into it to the specified action attribute. The uploaded files can be handled just as if there would have been a html input like this:

<input type="file" name="file" />

If you want another name than file you can configure Dropzone with the option paramName.

Configuration

When declaring a Dropzone like this, you might be wondering how to configure it then, and fortunately it's quite easy:

  1. Give the element that you want to configure an html id

  2. Setup the configuration on Dropzone.options

Example:

<script>
// Note that the name "myDropzone" is the camelized
// id of the form.
Dropzone.options.myDropzone = {
// Configuration options go here
};
</script>
<form action="/target" class="dropzone" id="my-dropzone"></form>

You can create as many options on Dropzone.options as you need — for each HTML element that you created, you can simply add the configuration.

For information on available configuration options, see the configuration section.

The "auto discover" feature

The way this works is called "auto discover". Dropzone checks when the DOM content finished loading, and then parses all HTML elements and looks for one with the class dropzone. If it finds an element, it checks if the element has an id. If it does, then it converst the id name to camel case (my-dropzone -> myDropzone) and checks if there is an entry in Dropzone.options with that key. If there is, then it uses that configuration object to instantiate the Dropzone for this object.

This behaviour can be disabled in two ways:

  1. Either set Dropzone.autoDiscover = false; somewhere in your JS. Just make sure it's invoked before the DOM ready event is dispatched.

  2. Set Dropzone.options.myDropzone = false; for individual dropzones. This allows you to use the auto discover feature, and only disable it for specific elements.

Dropzone parses the document when the document has finished loading, looks for elements that have the dropzone class, checks if there is a configuration in Dropzone.options for it, and then creates a Dropzone instance for that element. If all of that happened, before you defined your configuration, then Dropzone will miss the configuration. So make sure, that your configuration code is reached before Dropzone auto discovers these elements.

If you're not too keen on this approach, don't worry. Go to the next section to see how to create them imperatively.