[fix] title

src/view/iframe/publish/tool-box/child/editor.vue

@@ -142,6 +142,9 @@ const searchHandler = async () => {
 const getTitleByHtmlStr = (str) => {
   let index1 = str.indexOf('<title>') + 7;
   let index2 = str.indexOf('</title>');
+  if(index2 < 0) {
+    return '';
+  }
   return str.substring(index1, index2) || '';
 };