$(document).ready(function() {
    
    //Startimer
    var path = window.location.pathname;

    if(path.indexOf("sessie.php") === -1 && path.indexOf("logout.php") === -1)
    {
        if (sessionStorage.getItem("headerNR") === null)
        {
            x = 0;
        }
        else
        {
            x = parseInt(sessionStorage.getItem("headerNR"));

            //Set image
            document.getElementById("img").style.backgroundImage = "url('" + images[x] + "')";
        }
        
        startTimer();
    }
});

function displayNextImage() {
    
    x = (x === images.length - 1) ? 0 : x + 1;
    
    $(".navbar-background").fadeOut(300,

        function() {
        document.getElementById("img").style.backgroundImage = "url('" + images[x] + "')";
        $(".navbar-background").fadeIn(300);

            sessionStorage.setItem("headerNR", x);

        });
    }

function displayPreviousImage() {
	x = (x <= 0) ? images.length - 1 : x - 1;
    document.getElementById("img").style.backgroundImage = "url('" + images[x] + "')";
    }

function startTimer() {
	setInterval(displayNextImage, 10000);
    }

var images = [], x = -1;
images[0] = "/nav/background/royalpower.jpg";
images[1] = "/nav/background/laurensboessen.jpg";
images[2] = "/nav/background/royalnowornever.jpg";
images[3] = "/nav/background/molars.jpg";
images[4] = "/nav/background/statue.jpg";