Quick and dirty bootstrap state thing

bootstrapState

var bootstrapState = {
    current: null,
    last: null
};
_.extend(bootstrapState, Backbone.Events);

(function () {
    var last;
    
    function findState() {
        var envValues = ["xs", "sm", "md", "lg"];

        var $el = $('<div>');
        $el.appendTo($('body'));

        for (var i = envValues.length - 1; i >= 0; i--) {
            var envVal = envValues[i];

            $el.addClass('hidden-' + envVal);
            if ($el.is(':hidden')) {
                $el.remove();
                return envVal;
            }
        };

        return null;
    }

    var update = _.throttle(function () {
        var state = findState();
        if (last !== state) {
            bootstrapState.current = state;
            bootstrapState.last = last;
            bootstrapState.trigger('change', state, last);
            last = state;
        }

    }, 500);
    $(window).resize(update);
    update();
})();