让这个javascript在现代浏览器上工作

I'm trying to modernize an intranet site somebody has built in the past which at the moment is forced into compatibility mode for IE5 through group policy. There is this javascript which creates x ammount of file input boxes within a form. This works on compatibility mode up to IE9 but not higher. I don't really know javascript I was hoping someone could help me modernize it?I'm trying to modernize an intranet site somebo