Hi -

Throughout the book most input types are hidden/text, is it possible to pass an input object with type "file" to a server via JavaScript? I know it is not possible to write/edit/copy(?) file inputs for security reasons, but is it possible to build and submit a form "enctype=multipart/form-data" in order to get the file array populated for a web service to digest? Such as in "sendRequest()" on page 42?

I am writing a file upload web utility in .NET and would like to asynchronously upload a few files (or file byte streams?) and use some AJAX techniques to track the upload status.

Great AJAX book! Easy to read and follow. Maybe my question is covered in another Wrox book?

Thanks for any information,
- Joe

Joe,

You can't upload a file using XMLHttp since you have no access to the file data (other than the name) via JavaScript.

Nicholas C. Zakas
Author, Professional JavaScript for Web Developers (ISBN 0764579088)
http://www.nczonline.net/

I'm interested in this problem also. I'm writing a webmail system that encrypts messages using a Java applet. I'd like to be able to encrypt file uploads also but there doesn't seem to be any way to get access to the file data. Is there another technology that would make this possible?

Gmail has somehow passed a file input to another async thread to upload the file while you are composing your mail message. I have not figured out exactly how they've done it, yet.

You would have to use either an ActiveX control or Java applet with a custom upload mechanism to attempt such a thing.

As for Gmail's system, they aren't submitting the file via XMLHttp, they are actually submitting the file to a hidden frame.

Nicholas C. Zakas
Author, Professional JavaScript for Web Developers (ISBN 0764579088)
http://www.nczonline.net/