This is due to a security restriction.
I found out that the security restriction is only when the <input type="file"/>
is set to display:none;
or is visbilty:hidden
.
So i tried positioning it outside the viewport by setting position:absolute
and top:-100px;
and voilĂ it works.
see http://jsfiddle.net/DSARd/1/
call it a hack.
Hope that works for you.