How to call the OnChange event of "Select" ? (Delphi - WebBrowser) - html

Question

I'm using Delphi and WebBrowser componenet to navigate a html page . the page have a Combobox . is there any way to call the OnChange event ?
The ComboBox is like this :
<select name="comboname" onchange="Some Javascript codes">
Also , i have used this code :
function TFrmMain.SetComboboxValue(WB: TEmbeddedWB;
SelectName, ItemName: string): Boolean;
var
iForms, iFormItems, iSelectItems: Word;
FormItem: OleVariant;
begin
Result := false;
for iForms := 0 to WB.OleObject.Document.Forms.length - 1 do
begin
FormItem := WB.OleObject.Document.Forms.item(iForms);
for iFormItems := 0 to FormItem.length - 1 do
begin
if (FormItem.item(iFormItems). type = 'select-one') and SameText
(FormItem.item(iFormItems).Name, SelectName) then
begin
for iSelectItems := 0 to FormItem.item(iFormItems).Options.length - 1 do
begin
if SameText(FormItem.item(iFormItems).Options.item(iSelectItems)
.Text, ItemName) then
begin
FormItem.item(iFormItems).SelectedIndex := iSelectItems;
Result := true;
Break;
end;
end;
end;
end;
end;
end;
But it change the value only.

Answer 1

to execute the onchange event you can use the execScript method
check this sample
uses
MSHTML;
var
Doc: IHTMLDocument2;
HTMLWindow: IHTMLWindow2;
begin
Doc := WebBrowser1.Document as IHTMLDocument2;
if not Assigned(Doc) then
Exit;
HTMLWindow := Doc.parentWindow;
if not Assigned(HTMLWindow) then
Exit;
HTMLWindow.execScript('yourfunctioname()', 'JavaScript');
end;
for more info check this excellent article
How to call JavaScript functions in a TWebBrowser from Delphi

Answer 2

Inspired by the response. NET have been using the structures below:
FrameSet Document Elements Item Name Value Change ;
EWB.OleObject.Document.Frames.Item('mainFrame').Document.Forms.Item('invoiceForm').Elements.Item('inputname').Value:= '123456';
or
FrameSet Document Elements Items Lenth;
EWB.OleObject.Document.Forms.Item('invoiceForm').Elements.Length;