Improve forms, add helper buttons on add session form

games/static/js/add_session.js

@@ -0,0 +1,16 @@
+import { toISOUTCString } from "./utils.js";
+
+for (let button of document.querySelectorAll("[data-target]")) {
+  let target = button.getAttribute("data-target");
+  let type = button.getAttribute("data-type");
+  let targetElement = document.querySelector(`#id_${target}`);
+  button.addEventListener("click", (event) => {
+    event.preventDefault();
+    if (type == "now") {
+      targetElement.value = toISOUTCString(new Date);
+    } else if (type == "toggle") {
+      if (targetElement.type == "datetime-local") targetElement.type = "text";
+      else targetElement.type = "datetime-local";
+    }
+  });
+}