CompleteFTP supports HTTP file uploads to directories where uploads are permitted by the authenticated user. This uses the standard input element with type="file" in an HTML form. For example:
<FORM METHOD=POST ENCTYPE="multipart/form-data" ACTION=".">
<INPUT TYPE=FILE NAME="upfile"><INPUT TYPE=SUBMIT VALUE="Upload File">
</FORM>
If a directory is writable, the CompleteFTP directory listing page will include an HTML form permitting HTTP file uploads into this directory.