feat: support `frameset` element (#815)

src/content/blocksHandler/handlerSwitchTo.js

@@ -1,13 +1,15 @@
 import { isXPath } from '@/utils/helper';
 import handleSelector from '../handleSelector';
 
+const framesEl = ['IFRAME', 'FRAME'];
+
 function switchTo(block) {
   return new Promise((resolve, reject) => {
     block.data.findBy = isXPath(block.data.selector) ? 'xpath' : 'cssSelector';
 
     handleSelector(block, {
       onSelected(element) {
-        if (element.tagName !== 'IFRAME') {
+        if (!framesEl.includes(element.tagName)) {
           reject(new Error('not-iframe'));
           return;
         }