focus form items by following

src/content/follow.js

@@ -125,20 +125,13 @@ export default class Follow {
   }
 
   static getTargetElements(doc) {
-    let all = doc.querySelectorAll('a');
-    let filtered = Array.prototype.filter.call(all, (e) => {
-      return Follow.isVisibleElement(e);
+    let all = doc.querySelectorAll('a,button,input,textarea');
+    let filtered = Array.prototype.filter.call(all, (element) => {
+      let style = window.getComputedStyle(element);
+      return style.display !== 'none' &&
+        style.visibility !== 'hidden' &&
+        element.type !== 'hidden';
     });
     return filtered;
   }
-
-  static isVisibleElement(element) {
-    let style = window.getComputedStyle(element);
-    if (style.display === 'none') {
-      return false;
-    } else if (style.visibility === 'hidden') {
-      return false;
-    }
-    return true;
-  }
 }

src/content/index.js

@@ -11,11 +11,32 @@ consoleFrames.initialize(window.document);
 const startFollows = (newTab) => {
   let follow = new Follow(window.document, newTab);
   follow.onActivated((element) => {
-    browser.runtime.sendMessage({
-      type: messages.OPEN_URL,
-      url: element.href,
-      newTab
-    });
+    switch (element.tagName.toLowerCase()) {
+    case 'a':
+      return browser.runtime.sendMessage({
+        type: messages.OPEN_URL,
+        url: element.href,
+        newTab
+      });
+    case 'input':
+      switch (element.type) {
+      case 'file':
+      case 'checkbox':
+      case 'radio':
+      case 'submit':
+      case 'reset':
+      case 'button':
+      case 'image':
+      case 'color':
+        return element.click();
+      default:
+        return element.focus();
+      }
+    case 'textarea':
+      return element.focus();
+    case 'button':
+      return element.click();
+    }
   });
 };