From fb01a9122a6a104c509bf39fdee3803d778b67fd Mon Sep 17 00:00:00 2001
From: Johannes Stoelp <johannes.stoelp@gmail.com>
Date: Sat, 17 Feb 2024 02:36:49 +0100
Subject: html: tag filter example

---
 src/web/html.md       |  6 ++++++
 src/web/src/tags.html | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 src/web/src/tags.html

diff --git a/src/web/html.md b/src/web/html.md
index 4f545e1..d3b78ba 100644
--- a/src/web/html.md
+++ b/src/web/html.md
@@ -24,3 +24,9 @@
 ```html
 {{#include src/tabs.html }}
 ```
+
+# Minimal tags filter
+[Rendered html](src/tags.html)
+```html
+{{#include src/tags.html }}
+```
diff --git a/src/web/src/tags.html b/src/web/src/tags.html
new file mode 100644
index 0000000..25597ca
--- /dev/null
+++ b/src/web/src/tags.html
@@ -0,0 +1,60 @@
+<script>
+/// Map HTML elements to display kinds.
+const elementToDisplay = (E) => {
+    switch (E.nodeName) {
+        case "LI":
+            return "list-item";
+        default:
+            return "block";
+    }
+}
+
+/// Display only elements with tag T.
+const showTag = (T) => {
+    Array.from(document.getElementsByClassName("content")).forEach(E => {
+        E.style.display = "none";
+    });
+
+    Array.from(document.getElementsByClassName(T)).forEach(E => {
+        E.style.display = elementToDisplay(E);
+    });
+};
+
+/// Initialize buttons and callbacks.
+window.onload = () => {
+    // Handle to the filter placeholder.
+    const filter = document.getElementById("filter");
+
+    // Create buttons for each tag T.
+    ['arm', 'x86', 'clear'].forEach(T => {
+        const btn = document.createElement("button");
+        btn.innerHTML = T;
+        btn.onclick = T === "clear"
+            ? (E) => {
+                showTag("content");
+                filter.innerHTML = "";
+            }
+            : (E) => {
+                showTag(T);
+                filter.innerHTML = `<p>filter: <mark>${T}</mark></p>`;
+            };
+
+        document.body.prepend(btn);
+    });
+}
+</script>
+
+<div id = "filter"></div>
+
+<ul>
+    <li class = "content arm">arm 1</li>
+    <li class = "content arm">arm 2</li>
+    <li class = "content arm">arm 3</li>
+    <li class = "content x86">x86 1</li>
+    <li class = "content x86">x86 2</li>
+    <li class = "content x86 arm">x86 + arm</li>
+</ul>
+
+<div class = "content arm">arm</div>
+<div class = "content arm x86">arm x86</div>
+<div class = "content x86">x86</div>
-- 
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