This code works fine

$('#content').ajaxStart(function(){
	$(this).addClass('loading');
}).ajaxStop(function(){
	$(this).removeClass('loading');
});

but this doesn't:

$('body').ajaxStart(function(){
	$(this).addClass('loading');
}).ajaxStop(function(){
	$(this).removeClass('loading');
});

When attaching the event listeners to the body element it seems ajaxStop is not being triggered because the 'loading' class is not removed.

This, on the other hand, works fine:

$('#content').ajaxStart(function(){
	$('body').addClass('loading');
}).ajaxStop(function(){
	$('body').removeClass('loading');
});