add csrf token on every jQuery POST ajax request

jquery_django_ajax_csrf.js

// using jQuery
function getCookie(name) {
    var cookieValue = null;
    if (document.cookie && document.cookie != '') {
        var cookies = document.cookie.split(';');
        for (var i = 0; i < cookies.length; i++) {
            var cookie = jQuery.trim(cookies[i]);
            // Does this cookie string begin with the name we want?
            if (cookie.substring(0, name.length + 1) == (name + '=')) {
                cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
                break;
            }
        }
    }
    return cookieValue;
}

$.ajaxPrefilter(function(options, originalOptions, jqXHR){
    if (options['type'].toLowerCase() === "post") {
        jqXHR.setRequestHeader('X-CSRFToken', getCookie('csrftoken'));
    }
});