$(document).ready(function () {
	if ($('#signup').length>0) {	
	    var top = $('#signup').offset().top - parseFloat($('#signup').css('marginTop').replace(/auto/, 0));
	    $(window).scroll(function (event) {
	      // what the y position of the scroll is
	      var y = $(this).scrollTop();

	      // whether that's below the form
	      if (y >= top) {
	        // if so, ad the fixed class
	        $('#signup').addClass('fixed');
	      } else {
	        // otherwise remove it
	        $('#signup').removeClass('fixed');
	      }
	    });
	}
  });