How can I hide the Choose File button?

[elgs]

I expect the button css to be fully controlled by me. When I click on the button, a file chooser dialog should pop up. So is there any way I can hide the Choose File button? Thanks.

[elgs]

I modified the source code a little bit to make it like:

link: function (scope, element, attr) {
        var el = angular.element(element);
        var fileInput = angular.element('<input type="file" style="display: none;"/>');
        el.append(fileInput);
        element.on('click', function () {
          fileInput[0].click();
        });

It seems to work, but it should be an option.