jQuery click handlers
Apart from the fact I can't find any use of var loadPage It doesn't need to be an expression.
Instead try:

function loadPage(page) {
}


It is still accessible only within your code here, it is cleaner and easier to debug.
Keep your click events consistent

$(".sub-menu .menu-item, .module-item").click(function(event) {
    $(".page-content").load($(this).data('target'));  
    $("title").text( $( this ).text() );
});


Is the only place you're using .click( I'd stick with the $(parent).on('click', '.selector', function(){ style.