let ntpNav = document.querySelectorAll(".ntpBanner");

ntpNav.forEach((element) => {
    (<HTMLElement>element).onclick = function (){
        let contentID = element.getAttribute("data-index") + "-Content";
        let contentElement = <HTMLElement> document.getElementById(contentID);

        if(contentElement.classList.contains("visible")){
            contentElement.classList.remove("visible");
        } else {
            contentElement.classList.add("visible");
        }
    }
});