diff --git a/README.md b/README.md
index 3d5054c..448bb9b 100644
--- a/README.md
+++ b/README.md
@@ -185,25 +185,35 @@ new Disableautofill('#testForm', {
 
 ## Development
 
-### `npm run dev`
+#### `npm run dev`
 
 Starts a Vite server with hot reload.
 
-### `npm run lint`
+![](https://i.imgur.com/OeZhi6a.png)
+
+This page is the entry point of the development server. You can find it at `http://localhost:9527/`.
+
+#### `npm run lint`
 
 Executes linting by ESLint.
 
-### `npm run test`
+#### `npm run test`
 
 Runs tests by Vitest.
 
-### `npm run coverage`
+#### `npm run coverage`
 
 Runs coverage analysis by Vitest. Once you run this command, you can find the coverage report in the `coverage` directory.
 ```
 http://localhost:9527/coverage/
 ```
 
+You will see the coverage report like this:
+
+![](https://i.imgur.com/4vQxiB0.png)
+
+
+
 ### Using Docker
 
 If Docker is your preferred choice, here's what you need to know.
diff --git a/package.json b/package.json
index 0bcc005..9715871 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "disableautofill",
-  "version": "4.0.0-rc.2",
+  "version": "4.0.0-rc.3",
   "description": "The easiest solution for disabling Google Chrome auto-fill, auto-complete functions.",
   "main": "dist/disableautofill.umd.js",
   "module": "dist/disableautofill.es.js",
diff --git a/src/core/main.ts b/src/core/main.ts
index 4f82de7..1aa35cf 100644
--- a/src/core/main.ts
+++ b/src/core/main.ts
@@ -12,9 +12,13 @@ export default class Main {
   event: EventAdapter | null;
   state: State;
 
-  constructor(formSelector: string, options: Partial<Config>) {
+  constructor(form: string | HTMLFormElement, options: Partial<Config>) {
+    if (form instanceof HTMLFormElement) {
+      this.form = form;
+    } else {
+      this.form = document.querySelector(form) as HTMLFormElement;
+    }
     this.setting = { ...config, ...options };
-    this.form = document.querySelector(formSelector) as HTMLFormElement;
     this.clonedForm = this.form?.cloneNode(true) as HTMLFormElement;
     this.event = null;
     this.state = new State();
diff --git a/tests/units/main.test.js b/tests/units/main.test.js
index da52110..04eed4e 100644
--- a/tests/units/main.test.js
+++ b/tests/units/main.test.js
@@ -14,6 +14,12 @@ describe('Main class', () => {
     expect(main.form).not.toBeNull();
   });
 
+  test('should initialize with Form element', () => {
+    const form = document.querySelector('#login-form');
+    const main = new Main(form, {});
+    expect(main.form).not.toBeNull();
+  });
+
   test('should handle invalid form selector', () => {
     const originalConsoleError = console.error;
     console.error = vi.fn();