Tweaks.

Use urlencoded data for sending to server.

Improve outlook for progressive enhancement.

Add Cancel-link

templates/article_revision.html

@@ -8,10 +8,11 @@
 </div>
 <div class="editor">
     <form action="" method="POST">
-        <input type=hidden name=revision value="{{revision}}">
+        <input type=hidden name=baseRevision value="{{revision}}">
         <textarea autocomplete=off name=body>{{raw}}</textarea>
         <textarea autocomplete=off class="shadow-control"></textarea>
         <div class="editor-controls">
+            <a href="{{article_id}}">Cancel</a>
             <button type=submit>Save</button>
         </div>
     </form>
@@ -19,7 +20,7 @@
 </article>
 
 <footer>
-<p><a id="openEditor" href="?editor=true">Edit</a></p>
+<p><a id="openEditor" href="?editor">Edit</a></p>
 <dl>
     <dt>Article ID</dt>
     <dd>{{article_id}}</dd>
@@ -34,38 +35,64 @@
 
 <script>
 function autosizeTextarea(textarea, shadow) {
-    shadow.value = textarea.value;
     shadow.style.width = textarea.clientWidth + "px";
-    shadow.style.height = "auto";
+    shadow.value = textarea.value;
     textarea.style.height = shadow.scrollHeight + "px";
 }
 
+function queryArgsFromForm(form) {
+    const items = [];
+    for (const {name, value} of form.elements) {
+        if (!name) continue;
+        items.push(encodeURIComponent(name) + '=' + encodeURIComponent(value));
+    }
+    return items.join('&');
+}
+
 function openEditor() {
+    const article = document.querySelector("article");
     const rendered = document.querySelector(".rendered");
     const editor = document.querySelector(".editor");
     const textarea = editor.querySelector('textarea[name="body"]');
     const shadow = editor.querySelector('textarea.shadow-control');
 
-    editor.style.display = "block";
+    textarea.style.height = rendered.clientHeight + "px";
+
+    article.classList.add('edit');
 
     autosizeTextarea(textarea, shadow);
     textarea.addEventListener('input', () => autosizeTextarea(textarea, shadow));
     window.addEventListener('resize', () => autosizeTextarea(textarea, shadow));
 
-    rendered.style.display = "none";
-
     const form = editor.querySelector("form");
-    form.addEventListener("submit", async function (ev) {
+    form.addEventListener("submit", function (ev) {
+        (async function () {
             ev.preventDefault();
             ev.stopPropagation();
 
+            const body = queryArgsFromForm(form);
+            textarea.disabled = true;
+
             const response = await fetch(
                 form.getAttribute("action"),
                 {
                     method: 'PUT',
-                body: new FormData(form),
+                    headers: {
+                        "Content-Type": "application/x-www-form-urlencoded"
+                    },
+                    body: body,
                 }
             );
+
+            if (!response.ok) throw new Error("Unexpected status code (" + response.status + ")");
+
+            textarea.disabled = false;
+        }()
+        .catch(err => {
+            textarea.disabled = false;
+            console.error(err);
+            alert(err);
+        }));
     });
 
     textarea.focus();

templates/layout.html

@@ -142,12 +142,26 @@ textarea {
 .shadow-control {
     visibility: hidden;
     position: fixed;
+    height: auto;
+    min-height: 100px;
 }
 
 .editor {
     display: none;
 }
 
+.editor textarea {
+    height: 600px;
+}
+
+.edit .editor {
+    display: block;
+}
+
+.edit .rendered {
+    display: none;
+}
+
 .editor-controls {
     position: fixed;
     right: 0;
@@ -165,7 +179,7 @@ textarea {
         right: 20px;
         bottom: 20px;
 
-        box-shadow: 5px 5px 8px rgba(0,0,0, 0.3);
+        box-shadow: 2px 2px 8px rgba(0,0,0, 0.25);
     }
 }
 </style>