Manipulate Web Forms using the TWebBrowser

Web Forms and Web Element - from Delphi perspective

The TWebBrowser Delphi control provides access to the Web browser functionality from your Delphi apps - to allow you to create a customized Web browsing application or to add Internet, file and network browsing, document viewing, and data downloading capabilities to your applications.

Web Forms

A simplest web form could consist of one input element (edit control) and a submit button. Most web search engines (like Google) use such a web form to allow you to search the internet.

More complex web forms would include drop down lists, check boxes, radio buttons, etc. A web form is much like a standard windows form with text input and selection controls.

Every form would include a button - a submit button - a button that tells the browser to take action on the web form (typically to send it to a web server for processing).

Programmatically Populating Web Forms

Here's a collection of custom Delphi functions you can use to list all the web forms on a web page, to retrieve input elements, to programmatically populate fields and to finally submit the form.

To more easily follow the examples, let's say there's a TWebBrowser control named "WebBrowser1" on a Delphi (standard Windows) form.

Note: you should add mshtml to your uses clause in order to compile the methods listed here.

List Web Form Names, Get a Web Form by Index

function WebFormNames(const document: IHTMLDocument2): TStringList;
var
  forms : IHTMLElementCollection;
  form : IHTMLFormElement;
  idx : integer;
begin
  forms := document.Forms as IHTMLElementCollection;
  result := TStringList.Create;
  for idx := 0 to -1 + forms.length do
  begin
    form := forms.item(idx,0) as IHTMLFormElement;
    result.Add(form.name) ;
  end;
end;

var
  forms : TStringList;
begin
  forms := WebFormNames(WebBrowser1.Document AS IHTMLDocument2) ;
  try
    memo1.Lines.Assign(forms) ;
  finally
    forms.Free;
  end;
end;

Here's how to get the instance of a web form by index - for a single form pages the index would be 0 (zero).

function WebFormGet(const formNumber: integer; const document: IHTMLDocument2): IHTMLFormElement;
var
  forms : IHTMLElementCollection;
begin
  forms := document.Forms as IHTMLElementCollection;
  result := forms.Item(formNumber,'') as IHTMLFormElement
end;

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