[jquery] Show "loading" animation on button click

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

<form action="/process" method="POST">
   <input class="btn btn-large btn-primary" type="submit" value='Analyze Topics'>
    </form>

Now what I want is when the user presses this submit button. It shows that "loading" gif animation until it gets the response from server.

But I have been struggling since long time.

How do I implement this?

            //do processing
            $(this).attr("label", $(this).text()).text("loading ....").animate({ disabled: true }, 1000, function () {
                //original event call
                $.when($(elm).delay(1000).one("click")).done(function () {//processing finalized
                    $(this).text($(this).attr("label")).animate({ disabled: false }, 1000, function () {
                    })
                });
            });

The best loading and blocking that particular div for ajax call until it succeeded is Blockui

go through this link http://www.malsup.com/jquery/block/#element

example usage:

 <span class="no-display smallLoader"><img src="/images/loader-small.png" /></span>

script

jQuery.ajax(
{   
 url: site_path+"/restaurantlist/addtocart",
 type: "POST",
 success: function (data) {
   jQuery("#id").unblock(); 
},
beforeSend:function (data){
    jQuery("#id").block({ 
    message: jQuery(".smallLoader").html(), 
    css: { 
         border: 'none', 
         backgroundColor: 'none'
    },
    overlayCSS: { backgroundColor: '#afafaf' } 
    });

}
});

hope this helps really it is very interactive.

I know this a very much late reply but I saw this query recently And found a working scenario,

OnClick of Submit use the below code:

 $('#Submit').click(function ()
 { $(this).html('<img src="icon-loading.gif" />'); // A GIF Image of Your choice
 return false });

To Stop the Gif use the below code:

$('#Submit').ajaxStop();

If you are using ajax then (making it as simple as possible)

1. Add your loading gif image to html and make it hidden (using style in html itself now, you can add it to separate CSS):

   <img src="path\to\loading\gif" id="img" style="display:none"/ >
   

2. Show the image when button is clicked and hide it again on success function

   $('#buttonID').click(function(){
     $('#img').show(); //<----here
     $.ajax({
       ....
      success:function(result){
          $('#img').hide();  //<--- hide again
      }
   }
   

Make sure you hide the image on ajax error callbacks too to make sure the gif hides even if the ajax fails.

$("#btnId").click(function(e){
      e.preventDefault();
      $.ajax({
        ...
        beforeSend : function(xhr, opts){
            //show loading gif
        },
        success: function(){

        },
        complete : function() {
           //remove loading gif
        }
    });
});

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();
});