利用IPersist接口可以实现保存HTML到文件，在VB和Delphi下的实现是这样的：

VB:

Dim oPF As IPersistFile
Set oPF = WebBrowser1.Document
oPF.Save "TheFileNameHere.htm", False

Delphi: 

uses 
  MSHTML,OleCtrls, SHDocVw, StdCtrls,ActiveX; 
function GetHTMLCode(WB: IWebbrowser2; ACode: TStrings): Boolean; 
var 
  ps: IPersistStreamInit; 
  s: string; 
  ss: TStringStream; 
  sa: IStream; 
begin 
  ps := WB.document as IPersistStreamInit; 
  s := ''; 
  ss := TStringStream.Create(s); 
  try 
    sa:= TStreamAdapter.Create(ss, soReference) as IStream; 
    Result := Succeeded(ps.Save(sa, Bool(True))); 
    if Result then ACode.Add(ss.Datastring); 
  finally 
    ss.Free; 
  end; 
end;