I just had a very hard time trying to change my address on the JAL Mileage Bank page. They still had my address from about 4 years ago which changed at least a couple of times since then. When I tried to change it I realized why. I submitted the form, properly filled with full-width characters (including the digits) and on the confirmation screen I get the same form filled with mojibake asking me to complete it correctly. You have guessed already - nothing I type in there would actually help. Firebug to the rescue! I opened the form in Firebug, added an enctype="multipart/form-data" to the form element and surprise, surprise - my input was accepted.