Fix JS error when using keyboard arrows on "/releases/search" page

Author: GuillaumeGomez

static/index.js

@@ -5,40 +5,42 @@ function formatCrateName(crateTitleAndVersion) {
 
 (function() {
     const clipboard = document.getElementById("clipboard");
-    let resetClipboardTimeout = null;
-    let resetClipboardIcon = clipboard.innerHTML;
+    if (clipboard) {
+        let resetClipboardTimeout = null;
+        let resetClipboardIcon = clipboard.innerHTML;
 
-    function resetClipboard() {
-        resetClipboardTimeout = null;
-        clipboard.innerHTML = resetClipboardIcon;
-    }
-
-    function copyTextHandler() {
-        const crateTitleAndVersion = document.getElementById("crate-title");
-        // On rustdoc pages, we use `textTransform: uppercase`, which copies as uppercase.
-        // To avoid that, reset the styles temporarily.
-        const oldTransform = crateTitleAndVersion.style.textTransform;
-        crateTitleAndVersion.style.textTransform = "none";
-        const temporaryInput = document.createElement("input");
-
-        temporaryInput.type = "text";
-        temporaryInput.value = formatCrateName(crateTitleAndVersion.innerText);
-
-        document.body.append(temporaryInput);
-        temporaryInput.select();
-        document.execCommand("copy");
-
-        temporaryInput.remove();
-        crateTitleAndVersion.style.textTransform = oldTransform;
+        function resetClipboard() {
+            resetClipboardTimeout = null;
+            clipboard.innerHTML = resetClipboardIcon;
+        }
 
-        clipboard.textContent = "✓";
-        if (resetClipboardTimeout !== null) {
-            clearTimeout(resetClipboardTimeout);
+        function copyTextHandler() {
+            const crateTitleAndVersion = document.getElementById("crate-title");
+            // On rustdoc pages, we use `textTransform: uppercase`, which copies as uppercase.
+            // To avoid that, reset the styles temporarily.
+            const oldTransform = crateTitleAndVersion.style.textTransform;
+            crateTitleAndVersion.style.textTransform = "none";
+            const temporaryInput = document.createElement("input");
+
+            temporaryInput.type = "text";
+            temporaryInput.value = formatCrateName(crateTitleAndVersion.innerText);
+
+            document.body.append(temporaryInput);
+            temporaryInput.select();
+            document.execCommand("copy");
+
+            temporaryInput.remove();
+            crateTitleAndVersion.style.textTransform = oldTransform;
+
+            clipboard.textContent = "✓";
+            if (resetClipboardTimeout !== null) {
+                clearTimeout(resetClipboardTimeout);
+            }
+            resetClipboardTimeout = setTimeout(resetClipboard, 1000);
         }
-        resetClipboardTimeout = setTimeout(resetClipboard, 1000);
-    }
 
-    if (clipboard != null) clipboard.addEventListener("click", copyTextHandler);
+        clipboard.addEventListener("click", copyTextHandler);
+    }
     for (const e of document.querySelectorAll('a[data-fragment="retain"]')) {
         e.addEventListener('mouseover', () => e.hash = document.location.hash);
     }