Fix unexpected nav behaviour

static/js/nav.js

@@ -1,5 +1,15 @@
-document.getElementById("menu-button").addEventListener("click", function(){
+let element_button = document.getElementById("menu-button");
+let element_nav = document.getElementById("nav");
+let nav_items = document.getElementById("nav").getElementsByTagName("a");
+
+function toggle_menu() {
 	document.body.classList.toggle("noscroll");
-	this.getElementsByClassName("image")[0].classList.toggle("open");
-	document.getElementById("nav").classList.toggle("visible");
-});
+	element_button.getElementsByClassName("image")[0].classList.toggle("open");
+	element_nav.classList.toggle("visible");
+}
+
+element_button.addEventListener("click", toggle_menu);
+
+for (i = 0; i < nav_items.length; i++) {
+	nav_items[i].addEventListener("click", toggle_menu);
+}