var timer;
var currentTab = 1;
var numberOfTabs;

window.addEvent('domready', function() {
    timer = setTimeout("goToNews(2)", 7000);
    
    numberOfTabs = $('blub').innerHTML;
});


function goToNews(tab) {
    clearTimeout(timer);
    
    $('nieuws_item_' + currentTab).setStyle('display', "none");
    $('nieuws_item_' + tab).setStyle('display', "block");
    
    $('nieuws_item_date_' + currentTab).setStyle('display', "none");
    $('nieuws_item_date_' + tab).setStyle('display', "block");
    
    currentTab = tab;
    
    nextTab = currentTab + 1;
    if (nextTab > numberOfTabs) {
        nextTab = 1;
    }
    timer = setTimeout("goToNews(" + nextTab + ")", 7000);
}



function goToPrev() {
    clearTimeout(timer);
    
    nextTab = currentTab - 1;
    if (nextTab == 0) {
        nextTab = numberOfTabs;
    }
    goToNews(nextTab);
}

function goToNext() {
    clearTimeout(timer);
    
    nextTab = currentTab +1;
    if (nextTab > numberOfTabs) {
        nextTab = 1;
    }
    goToNews(nextTab);
}