Modify input type file height


Is there a way to modify the <input type=“file” /> height so I can use the hidden input method and put a big button over it?
I could successfully set the height in IE 8/9 & Chrome but not Firefox (it uses an !important line-height internally ).

I can’t use the javascript .click() method because IE blocks it so I’m at a loss here…

Thank you in advance for your help!

Sample I found on the internet :
If you click on the bottom part of the rectangle with Firefox, you’ll notice the file selection dialog doesn’t open. :x