Frequently Asked Questions

Does the plugin have to be called on a form tag?

Technically, the form is only required for iframe uploads. If you define the url, method and fieldName Options, you can call the plugin on any element - no form or file input field required - and the drag and drop functionality will still work. The file input button functionality would technically also work without a form, but the plugin code currently requires the file input to be part of a form. But without support for iframe uploads, you will leave users of IE and Opera out in the dark.

However, what you can do is using the dropZone option to define a container inside of the form as dropZone target. You can also adjust the CSS code so the file input field does not cover the whole form.

Please have a look at How to submit additional Form Data, specifically the second section about "Sending additional Form Data by adding input fields to the upload form".

Internet Explorer prompts to download a file after the upload completes - why?

The file upload plugin makes use of iframes for browsers like Microsoft Internet Explorer and Opera, which do not yet support XMLHTTPRequest uploads. They will only register a load event if the Content-type of the response is set to text/plain or text/html, not if it is set to application/json. Setting the content-type of the JSON response to "text/html" should usually fix problems where IE shows an unwanted download dialog.
Please have a look at the Setup instructions.

Why do I get a JSON parsing error?

Your JSON response is probably not valid JSON.
You can test your JSON response for validity on jslint.com.