diff --git a/src/chrome-extension/lib/tabs.ts b/src/chrome-extension/lib/tabs.ts
index 5ac5d1b..f6d0e97 100644
--- a/src/chrome-extension/lib/tabs.ts
+++ b/src/chrome-extension/lib/tabs.ts
@@ -19,7 +19,7 @@ class Tabs {
   }
 
   getExtraInfo (id: number) {
-    return (this.getTab(id) && this.getTab(id).extraInfo) ? this.getTab(id).extraInfo : 0;
+    return (this.getTab(id) && this.getTab(id).extraInfo) ? this.getTab(id).extraInfo : {};
   }
 
   getFileName (id: number) {
diff --git a/src/chrome-extension/typing/background.d.ts b/src/chrome-extension/typing/background.d.ts
index e955913..fff4f44 100644
--- a/src/chrome-extension/typing/background.d.ts
+++ b/src/chrome-extension/typing/background.d.ts
@@ -17,5 +17,5 @@ export interface IWebPageMessages {
   fileName?: string;  // Record saved file name
   pageWidth?: number; // The width of the page
   pageHeight?: number; // The height of the page
-  extraInfo?: any;  // Additional information to carry
+  extraInfo?: IRecursive;  // Additional information to carry
 }