Check in copy.js

apps/i2ptunnel/jsp/js/copy.js

@@ -0,0 +1,37 @@
+/* @license http://www.gnu.org/licenses/gpl-2.0.html GPL-2.0 */
+/* see also licenses/LICENSE-GPLv2.txt */
+
+function initCopyLink() {
+        var buttons = document.getElementsByClassName("tunnelHostnameCopy");
+        for (index = 0; index < buttons.length; index++) {
+                var button = buttons[index];
+                addClickHandler(button);
+        }
+}
+
+function addClickHandler(elem) {
+        elem.addEventListener("click", function() {
+              let prevElem = getPreviousHelper(elem).firstElementChild;
+              prevElem.select();
+              document.execCommand("copy");
+              alert("Copied the helper to the clipboard", prevElem.value);
+        });
+}
+
+document.addEventListener("DOMContentLoaded", function() {
+    initCopyLink();
+}, true);
+
+var getPreviousHelper = function (elem) {
+        var selector = ".tunnelPreview";
+        var parent = elem.parentElement
+        var sibling = parent.previousElementSibling;
+        while (sibling) {
+                if (sibling.matches(selector)) return sibling;
+                sibling = sibling.previousElementSibling;
+        }
+        return sibling
+};
+
+
+/* @license-end */