JAVASCRIPT

display loader on ajax call

$.ajax({
  url        : url,
  cache      : false,
  beforeSend : function(){
    $('#loading-image').show();
  },
  success: function(html){
    $('#loading-image').hide();
    $('.info').append(html);
  },
});

ajax loader

// Setting up a loading indicator using Ajax Events
$( "#loading_indicator" )
    .ajaxStart(function() {
        $( this ).show();
    })
    .ajaxStop(function() {
        $( this ).hide();
    });