How to hide elements when another element is clicked

Having a bit of difficulty getting this jquery to work. I have a form where all fields are nested in a div.form-group. The subscribe button has an id of subscribe.

I want the form fields to disappear on click... but my js is not working out. Here's what I've tried, to no avail:

(function($) {
    window.onload = function () {
        $("#subscribe").click(function() {
            $(".form-group").css("display: none");
        });
    }
})(jQuery);

The form-group class is set to display: block in the CSS.

Is there something obvious I'm missing here? Any help is greatly appreciated.

cheers,