Ye' old general discussion board. Basically, for everything that isn't covered elsewhere. Come here to shoot the breeze, shoot your mouth off, or whatever suits your fancy. This forum is not for asking programming related questions.
You've used the new "multiple" attribute on your file input element (a feature of HTML5) yet unless I am mistaken the web page itself is XHTML 1.0 Transitional and so that's actually invalid.