Show “loading” animation on button click

Question

I want to do something very simple. I have one button in my page.

Answer 1

try

$("#btnId").click(function(e){
 e.preventDefault();
 //show loading gif

 $.ajax({
  ...
  success:function(data){
   //remove gif
  },
  error:function(){//remove gif}

 });
});

EDIT: after reading the comments

in case you decide against ajax

$("#btnId").click(function(e){
     e.preventDefault();
     //show loading gif
     $(this).closest('form').submit();
});