title	Documentation Overview
parent	WebView2 Package
nav_order	2

WebView2 Technical Documentation

twinBASIC WebView2 package provides complete Microsoft Edge WebView2 control integration, enabling you to embed modern web content in twinBASIC applications and achieve bidirectional interaction.

Documentation Index

Core Documents

Document	Description
Getting Started Guide	Quick start with WebView2 control
Index	Documentation index and functionality overview

Class References

Document	Description
WebView2 Control	Main control class, complete reference of all properties, methods, and events
Environment Options	WebView2 environment configuration options

HTTP Related

Document	Description
HTTP Request	Web resource request object
HTTP Response	Web resource response object
Request Headers	HTTP request header management
Response Headers	HTTP response header management
Header Collection	HTTP header collection enumeration
Header Info	Single HTTP header information

Advanced Topics

Document	Description
Enumeration Types	All enumeration type definitions and descriptions
Deferred Callback	Deferred event and callback mechanism (re-entrancy issues)

Quick Navigation

I Want to...

Display a Web Page

WebView21.Navigate "https://www.example.com"

→ Refer to WebView2 Control - Navigation Methods

Execute JavaScript

Dim result As Variant
result = WebView21.JsRun("document.title")

→ Refer to WebView2 Control - JavaScript Interaction

Communicate Between Twinbasic and JavaScript

' Twinbasic sends to JavaScript
WebView21.PostWebMessage "Hello!"

' JavaScript sends to Twinbasic
window.chrome.webview.postMessage("Hello from JS");

→ Refer to WebView2 Control - Message Passing

Intercept HTTP Requests

WebView21.AddWebResourceRequestedFilter "*://*/*.png", wv2Image

Private Sub WebView21_WebResourceRequested(ByVal Request As WebView2Request, _
    ByVal Response As WebView2Response)
    ' Handle request
End Sub

→ Refer to WebView2 Control - Web Resource Interception

Customize Right-Click Menu

Private Sub WebView21_UserContextMenu(X As Single, Y As Single)
    PopupMenu mnuCustomContext, vbPopupMenuRightButton, X, Y
End Sub

→ Refer to WebView2 Control - Events

Print to PDF

WebView21.PrintToPdf "C:\output.pdf"

→ Refer to WebView2 Control - Advanced Features

Configure Environment Options

WebView21.EnvironmentOptions.UserDataFolder = "C:\MyApp\Data"
WebView21.EnvironmentOptions.Language = "en-US"

→ Refer to Environment Options

Core Class Diagram

WebView2 (Main Control)
├── WebView2EnvironmentOptions (Environment Configuration)
├── WebView2Request (HTTP Request)
│   └── WebView2RequestHeaders (Request Headers)
│       └── WebView2HeadersCollection (Header Collection)
│           └── WebView2Header (Single Header)
└── WebView2Response (HTTP Response)
    └── WebView2ResponseHeaders (Response Headers)
        └── WebView2HeadersCollection (Header Collection)
            └── WebView2Header (Single Header)

Main Functionality Modules

1. Web Content Display

✅ Load URL web pages
✅ Load custom HTML strings
✅ Virtual host mapping
✅ PDF export

2. Navigation Control

✅ Forward/backward navigation
✅ Page refresh
✅ Custom HTTP requests (POST, Headers)

3. JavaScript Interaction

✅ Execute JavaScript code
✅ Synchronously call JS functions
✅ Asynchronously call JS functions
✅ Bidirectional message passing

4. Object Sharing

✅ Expose COM objects to JavaScript
✅ Deferred invocation mode (avoid re-entrancy)

5. Event Handling

✅ Navigation events
✅ Permission request events
✅ Script dialog events
✅ Download events
✅ Web resource interception

6. Advanced Features

✅ Developer tools
✅ DevTools protocol
✅ Download manager
✅ Task manager
✅ Audio control
✅ Suspend/resume

Development Workflow

Step 1: Environment Setup

Install WebView2 Runtime
Reference WebView2 package
Add WebView2 control to form

→ Refer to Getting Started

Step 2: Basic Navigation

Private Sub Form_Load()
    ' Note: All WebView21 member operations must be done after WebView21_Ready()
End Sub

Private Sub WebView21_Ready()
    WebView21.DocumentURL = "https://www.example.com"
End Sub

Private Sub WebView21_NavigationComplete(ByVal IsSuccess As Boolean, _
    ByVal WebErrorStatus As Long)
    ' Page loading complete
End Sub

Step 3: JavaScript Interaction

' Execute JS
WebView21.ExecuteScript "document.body.style.background = 'red'"

' Get JS return value
Dim title As Variant
title = WebView21.JsProp("document.title")

Step 4: Bidirectional Communication

' Twinbasic sends to JavaScript
WebView21.PostWebMessage "Hello"

Private Sub WebView21_JsMessage(ByVal Message As Variant)
    ' Receive JavaScript message
End Sub

Step 5: Advanced Features

Intercept HTTP requests
Customize right-click menu
Print PDF
Virtual host mapping

Common Questions

1. Control Not Displaying

Make sure to set Visible = True and properly set position and size.

2. Page Loading Failed

Check if WebView2 Runtime is installed and review the Error event.

3. JavaScript Call Timeout

Set JsCallTimeOutSeconds property to increase timeout.

4. Re-entrancy Problems

Use UseDeferredEvents = True and use UseDeferredInvoke = True in AddObject.

5. Permission Requests

Handle permission requests in the PermissionRequested event.

Dependency Requirements

Windows 7 SP1 or higher
WebView2 Runtime (Evergreen) 86.0.616.0 or higher

License

The WebView2 package follows its own license terms, see the LICENCE.md file in the package for details.

Feedback and Support

For questions or suggestions, please provide feedback through:

Submit an Issue
Visit twinBASIC community

Documentation Updates

Last updated: February 15, 2026

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