Added example of chrome.i18n.detectLanguage

chrome/common/extensions/docs/examples/api/i18n/detectLanguage/popup.js

+
+document.addEventListener('DOMContentLoaded', function() {
+  document.getElementById("btn-detect").addEventListener("click", function() {
+    var inputText = document.getElementById("text").value;
+    chrome.i18n.detectLanguage(inputText, function(result) {
+        var languages =  "Languages: \n";
+        for (var i = 0; i < result.languages.length; i++) {
+           languages += result.languages[i].language + " ";
+           languages += result.languages[i].percentage + "\n";
+        }
+
+        var is_reliable = "\nReliable? \n" + result.isReliable + "\n";
+        alert(languages + is_reliable);
+    });
+  });
+});