function initiate() {
  for (let f = 1; f < 5; f++) {
    const span = document.getElementById("url" + f);
    span.addEventListener("click", function () {
      navigation.navigate("page" + f + ".html", { state: f });
    });
  }
  navigation.addEventListener("navigate", function (event) {
    if (!event.canIntercept) {
      return;
    }
    event.intercept({
      handler() {
        const content = event.destination.getState();
        showcontent(content);
      }
    });
  });
}
function showcontent(current) {
  const image = document.getElementById("image");
  image.src = "monster" + current + ".jpg";
}
window.addEventListener("DOMContentLoaded", initiate);