TCppWebBrowser  Click button on page

 This is the web form source :
input type="submit" name="Button1" value="LogOut"
 onclick="return confirm(" Are you Sure you want to logout ?");" id="Button1" 
 
 
 
and this is my source code to press the button :
 
void __fastcall TForm1::Button3Click(TObject *Sender)
{
	PresstheButton("Button1", 0);
}
 
void PresstheButton(String FieldName, int Option)
{
	// Obtain the IHTMLDocument2 from the Web Browser
	TComInterface<IHTMLDocument2>PageDoc;
	Form1->CppWebBrowser1->Document->QueryInterface
		(IID_IHTMLDocument2, (LPVOID*) & PageDoc);
 
	if (PageDoc)
	{
		// Obtain a list of all the elements
		TComInterface<IHTMLElementCollection>All;
		PageDoc->get_all(&All);
		if (All)
		{
			// Get the first element i.e. TVariant(0) with the given FieldName
			TComInterface<IDispatch>Disp;
			All->item(TVariant(WideString(FieldName)), TVariant(Option), &Disp);
 
			if (Disp)
			{
				TComInterface<IHTMLInputElement>InputElement;
				Disp->QueryInterface(IID_IHTMLInputElement, (LPVOID*)
					& InputElement);
 
				if (InputElement)
				{
					// Check the Button 
					InputElement->put_checked(1);
					DISPID idMethod[1];
					LPOLESTR FnName[1] =
					{
						L"OnClick"
					};
					if (InputElement->GetIDsOfNames(IID_NULL, FnName, 1,
							LOCALE_SYSTEM_DEFAULT, idMethod) == 0)
					{
						DISPPARAMS dpNoArgs =
						{
							NULL, NULL, 0, 0
						};
						InputElement->Invoke(idMethod[0], IID_NULL,
							LOCALE_SYSTEM_DEFAULT, DISPATCH_METHOD, &dpNoArgs,
							NULL, NULL, NULL);
					}
				}
			}
		}
	}
}