Как с помощью IWebBrowser2 получить доступ к элементам HTML-страницы?

{
This example shows how to automatically fill in a search string
in the "Search Tip" page and click the search button.
}

uses
MSHTML_TLB;

// first navigate to tipspage

procedure TForm1.Button1Click(Sender: TObject);
begin
Webbrowser1.Navigate('http://www.swissdelphicenter.ch/en/tipsuchen.php');
end;

// Try to access IE instance and fill out the search field with
// a text and click the search button

procedure TForm1.Button3Click(Sender: TObject);
var
hIE: HWND;
ShellWindow: IShellWindows;
WB: IWebbrowser2;
spDisp: IDispatch;
IDoc1: IHTMLDocument2;
Document: Variant;
k, m: Integer;
ovElements: OleVariant;
i: Integer;
begin
ShellWindow := CoShellWindows.Create;
// get the running instance of Internet Explorer
for k := 0 to ShellWindow.Count do
begin
spDisp := ShellWindow.Item(k);
if spDisp = nil then Continue;
// QueryInterface determines if an interface can be used with an object
spDisp.QueryInterface(iWebBrowser2, WB);

if WB <> nil then
begin
WB.Document.QueryInterface(IHTMLDocument2, iDoc1);
if iDoc1 <> nil then
begin
WB := ShellWindow.Item(k) as IWebbrowser2;
begin
Document := WB.Document;

// count forms on document and iterate through its forms
for m := 0 to Document.forms.Length - 1 do
begin
ovElements := Document.forms.Item(m).elements;
// iterate through elements
for i := 0 to ovElements.Length - 1 do
begin
// when input fieldname is found, try to fill out
try
if (CompareText(ovElements.item(i).tagName, 'INPUT') = 0) and
(CompareText(ovElements.item(i).type, 'text') = 0) then
begin
ovElements.item(i).Value := 'FindWindow';
end;
except
end;
// when Submit button is found, try to click
try
if (CompareText(ovElements.item(i).tagName, 'INPUT') = 0) and
(CompareText(ovElements.item(i).type, 'SUBMIT') = 0) and
(ovElements.item(i).Value = 'Search') then // Suchen fьr German
begin
ovElements.item(i).Click;
end;
except
end;
end;
end;
end;
end;
end;
end;
end;

Много хороших примеров в дельфийском DRKB, оттуда можно буквально копипастить. После чего есть смысл посмотреть на reference по интерфейсам IHTML* в MSDN - там находится _вся_ остальная информация.