Disable JavaScript error in WebBrowser control

webBrowser.ScriptErrorsSuppressed = true;

This disables the script errors and also disables other windows.. such as the NTLM login window or the client certificate accept window. The below will suppress only javascript errors.

// Hides script errors without hiding other dialog boxes.
private void SuppressScriptErrorsOnly(WebBrowser browser)
{
    // Ensure that ScriptErrorsSuppressed is set to false.
    browser.ScriptErrorsSuppressed = false;

    // Handle DocumentCompleted to gain access to the Document object.
    browser.DocumentCompleted +=
        new WebBrowserDocumentCompletedEventHandler(
            browser_DocumentCompleted);
}

private void browser_DocumentCompleted(object sender, 
    WebBrowserDocumentCompletedEventArgs e)
{
    ((WebBrowser)sender).Document.Window.Error += 
        new HtmlElementErrorEventHandler(Window_Error);
}

private void Window_Error(object sender, 
    HtmlElementErrorEventArgs e)
{
    // Ignore the error and suppress the error dialog box. 
    e.Handled = true;
}