$(function() {
$(".fade-in").css("opacity","0"); // opacity of button set to 0%
$(".fade-in").hover(function () { // onmouseover
$(this).stop().animate({ // set opacity to 100%
  opacity: 1.0
  }, "normal");
},

function () { // onmouseout
$(this).stop().animate({ // set opacity back to 0%
  opacity: 0
  }, "slow");
});
});