Backbone loading spinner. First go and create and install a spinner on the spin.js website.

css.css

#loading{
    position:fixed;
    z-index:999;
    top:0;
    left:0;
    width:100%;
    height: 100%;
    background:rgba(0,0,0,0.3);
}

html.html

<div id="loading"></div>

js.js

$(function(){
    $("#loading").spin({/* YOUR SPINNER OPTIONS */}).hide();
    $('#loading').ajaxStart(function(){ $(this).fadeIn(); });
    $('#loading').ajaxComplete(function(){ $(this).fadeOut(); });
});