feat: add secure Pi-hole DNS management

internal/web/static/app.js

@@ -179,6 +179,25 @@
     });
   }
 
+  for (const form of document.querySelectorAll('[data-dirty-form]')) {
+    const submit = form.querySelector('[data-dirty-submit]');
+    if (!submit) continue;
+    const state = () => new URLSearchParams(new FormData(form)).toString();
+    const initialState = state();
+    const syncDirtyState = () => {
+      const dirty = state() !== initialState;
+      submit.disabled = !dirty;
+      submit.setAttribute('aria-disabled', String(!dirty));
+    };
+    form.addEventListener('input', syncDirtyState);
+    form.addEventListener('change', syncDirtyState);
+    form.addEventListener('submit', (event) => {
+      syncDirtyState();
+      if (submit.disabled) event.preventDefault();
+    });
+    syncDirtyState();
+  }
+
   const copyButtons = document.querySelectorAll('[data-copy-target]');
   for (const button of copyButtons) {
     button.addEventListener('click', async () => {