以下是示范如何读取及提交TWebBrowser中的网页
示例内容:
- 获得网页中表单(form)的数量
- 按编号从页面中获取表单
- 按编号得到表单的名称
- 按名称提取表单
- 获取表单中所有字段的名称
- 获取表单中指定名称的字段的值
- 设置表单中指定名称的字段的值
- 提交表单
以下的示例假设TWebBrowser被命名为WebBrowser而且网页被已经打开.
获得网页中表单(form)的数量
function NumberOfForms(document: IHTMLDocument2): integer;var forms: IHTMLElementCollection;begin forms := document.Forms as IHTMLElementCollection; result := forms.Length;end;
按编号从页面中获取表单
网页中可能会有多个表单,表单的编号从零开始
function GetFormByNumber(document: IHTMLDocument2; formNumber: integer): IHTMLFormElement;var forms: IHTMLElementCollection;begin forms := document.Forms as IHTMLElementCollection; if formNumber < forms.Length then result := forms.Item(formNumber,'') as IHTMLFormElement else result := nil;end;
按编号得到表单的名称
var firstForm: IHTMLFormElement; document: IHTMLDocument2;begin document := WebBrowser.Document as IHTMLDocument2; firstForm := GetFormByNumber(document,0); if Assigned(firstForm) then ShowMessage('这个表单的名称是' + firstForm.Name) else ShowMessage(这个页面不包含任何表单'); 按名称提取表单
如果知道表单的名称就可以直接按名称提取表单
function GetFormByName(document: IHTMLDocument2; const formName: string): IHTMLFormElement;var forms: IHTMLElementCollection;begin forms := document.Forms as IHTMLElementCollection; result := forms.Item(formName,'') as IHTMLFormElementend;
如果网页中不包含表单则返回nil
获取表单中所有字段的名称
function GetFormFieldNames(fromForm: IHTMLFormElement): TStringList;var index: integer; field: IHTMLElement; input: IHTMLInputElement; select: IHTMLSelectElement; text: IHTMLTextAreaElement;begin result := TStringList.Create; for index := 0 to fromForm.length do begin field := fromForm.Item(index,'') as IHTMLElement; if Assigned(field) then begin if field.tagName = 'INPUT' then begin // Input field. input := field as IHTMLInputElement; result.Add(input.name); end else if field.tagName = 'SELECT' then begin // Select field. select := field as IHTMLSelectElement; result.Add(select.name); end else if field.tagName = 'TEXTAREA' then begin // TextArea field. text := field as IHTMLTextAreaElement; result.Add(text.name); end; end; end;end;
应用:
procedure TMyForm.Button1Click(Sender: TObject);var document: IHTMLDocument2; theForm: IHTMLFormElement; index: integer;begin document := TWebBrowser.Document as IHTMLDocument2; theForm := GetFormByNumber(WebBrowser.Document as IHTMLDocument2,0); fields := GetFormFieldNames(theForm); for index := 0 to fields.count-1 do ShowMessage('Field ' + IntToStr(index) + ' called ' + fields[index]);end; 获取表单中指定名称的字段的值
function GetFieldValue(fromForm: IHTMLFormElement; const fieldName: string): string;var field: IHTMLElement; inputField: IHTMLInputElement; selectField: IHTMLSelectElement; textField: IHTMLTextAreaElement;begin field := fromForm.Item(fieldName,'') as IHTMLElement; if not Assigned(field) then result := '' else if field.tagName = 'INPUT' then begin inputField := field as IHTMLInputElement; if (inputField.type_ <> 'radio') and (inputField.type_ <> 'checkbox') then result := inputField.value else if inputField.checked then result := 'checked' else result := 'unchecked'; end else if field.tagName = 'SELECT' then begin selectField := field as IHTMLSelectElement; result := selectField.value end else if field.tagName = 'TEXTAREA' then begin textField := field as IHTMLTextAreaElement; result := textField.value; end;end;
应用:
procedure TMyForm.Button1Click(Sender: TObject); var document: IHTMLDocument2; theForm: IHTMLFormElement; index: integer; begin document := TWebBrowser.Document as IHTMLDocument2; theForm := GetFormByNumber(WebBrowser.Document as IHTMLDocument2,0); ShowMessage('Field "name" has value ' + GetFieldValue(theForm,'name'));
"GetFieldValue" 函数在猎取字段值之前先判断该字段的类型,如果已知字段类型,该函数可以被简化,
举例说如果你确定字段是一个input字段,
function GetInputField(fromForm: IHTMLFormElement; const inputName: string; const instance: integer=0): HTMLInputElement; var field: IHTMLElement; begin field := fromForm.Item(inputName,instance) as IHTMLElement; if Assigned(field) then begin if field.tagName = 'INPUT' then begin result := field as HTMLInputElement; exit; end; end; result := nil; end;
设置表单中指定名称的字段的值
procedure SetFieldValue(theForm: IHTMLFormElement; const fieldName: string; const newValue: string; const instance: integer=0);var field: IHTMLElement; inputField: IHTMLInputElement; selectField: IHTMLSelectElement; textField: IHTMLTextAreaElement;begin field := theForm.Item(fieldName,instance) as IHTMLElement; if Assigned(field) then begin if field.tagName = 'INPUT' then begin inputField := field as IHTMLInputElement; if (inputField.type_ <> 'radio') and (inputField.type_ <> 'checkbox') then inputField.value := newValue else inputField.checked := (newValue = 'checked'); end else if field.tagName = 'SELECT' then begin selectField := field as IHTMLSelectElement; selectField.value := newValue; end else if field.tagName = 'TEXTAREA' then begin textField := field as IHTMLTextAreaElement; textField.value := newValue; end; end;end;
应用:
procedure TMyForm.Button1Click(Sender: TObject); var document: IHTMLDocument2; theForm: IHTMLFormElement; index: integer; begin document := TWebBrowser.Document as IHTMLDocument2; theForm := GetFormByNumber(WebBrowser.Document as IHTMLDocument2,0); SetFieldValue(theForm,'name','Brian Cryer');
提交表单
最后一件事就是向服务器提交表单:
procedure TMyForm.Button1Click(Sender: TObject);var document: IHTMLDocument2; theForm: IHTMLFormElement; index: integer;begin document := TWebBrowser.Document as IHTMLDocument2; theForm := GetFormByNumber(document,0); SetFieldValue(theForm,'name','Brian Cryer'); theForm.submit;