Target last li in row?

function calculateLIsInRow() {
    var lisInRow = 0;
    $('ul li').each(function() {
        $(this).removeClass("back");
        if($(this).prev().length > 0) {
            if($(this).position().top != $(this).prev().position().top) {
               $(this).prev().addClass("back");
               // return false;
            }
            lisInRow++;
        } else {
            lisInRow++;   
        }
        if($(this).next().length > 0) {
        }
        else {
            $(this).addClass("back");
        }
    });
}

calculateLIsInRow();

$(window).resize(calculateLIsInRow);

JSFIDDLE

I think i have found the answer .. Please check by resizing the window..

Check this function (I had the same problem once and made this function, you may edit it as you want): EDIT WORKING ON RESIZE

DEMO (resize)

var wrapDetector = function(element) {
var $elem = $(element);
var wrapper = $(element).parent();
var wrapperWidth = wrapper.outerWidth();
var expToggle = $('#main-menu-wrapper.main-menu-expanded #header-toggle-buttons');
wrapper.attr('data-width', wrapperWidth);
var elemTotalWidth = 0;
$elem.each(function() {
    elemTotalWidth += $(this).outerWidth();
});

var wrapperWidthNew = wrapper.outerWidth();
var curWidth = 0;        
$elem.removeClass('lastInRow last-row');
$elem.each(function() {
    var that = $(this);
    var elemWidth = that.outerWidth();
    curWidth += elemWidth;        
    if (curWidth > wrapperWidthNew) {
        that.prev().addClass('lastInRow');
        curWidth = elemWidth;
    }
    that.attr('data-curWidth', curWidth);        
});
var lastInRow = $(element + '.lastInRow');

if (lastInRow.length > 0) {
    lastInRow.last().nextAll().addClass('last-row');        
} else {
    $elem.addClass('last-row');
}
}

wrapDetector('li');  

ADD THIS

$(window).resize(function() {
  wrapDetector('li');
});