var currentHeaderImage = 0;

function onDocReady() {
    setInterval(fadeNextImageIn, 2000);
}

function fadeNextImageIn() {
    $("span.tabOn").addClass("tabOff").removeClass("tabOn");
    $("div.tab").fadeOut();
    if ($("#tab_" + currentHeaderImage + "_content").length == 0) {
        currentHeaderImage = 0;
    }
    var currentTabJQ = $("#tab_" + currentHeaderImage + "_content");
    currentTabJQ.stop();
    currentTabJQ.fadeIn();
    $("span#tab_" + currentHeaderImage).addClass("tabOn");
    currentHeaderImage += 1;

}

$(document).ready(onDocReady);