How to analyze page elements and handle them accordingly

How to analyze the elements of the Web page, and then do the appropriate processing, such as filling, submitting, etc.

#include <Mshtml.h>
ansistring __fastcall tform3::submit (void)
{
IHTMLDocument2 *phtmldoc = NULL;
Lpdispatch pdisp = NULL;
Pdisp =cppwebbrowser1->document;
if (pdisp)
{
if (succeeded Pdisp->queryinterface (Iid_ihtmldocument2, (void**) &phtmldoc))
{
Pdisp->release ();
IHTMLElementCollection *pelement;
if (phtmldoc->get_forms (&pelement)!=S_OK)
{
Phtmldoc->release ();
Pdisp->release ();
Pelement->release ();
Return "1 send failure";
}
Pdisp->release ();
tagVARIANT A,i;
A.VT=VT_UI4;
a.lval=0;//This value is the order of the form you want to fill out throughout the page, 0 is the first form
if (Pelement->item (a,i,&pdisp)!=S_OK)
{
Pelement->release ();
Pdisp->release ();
Return "2 send Failure";
}
Pelement->release ();
ihtmlformelement* Pformelem=null;
if (pdisp)
{
if (! Succeeded (Pdisp->queryinterface (Iid_ihtmlformelement, (lpvoid*) &pformelem))
{
Pformelem->release ();
Pdisp->release ();
Return "3 Send Failure";
}
}
Else
{
Return "31 Send Failure";
}
Pdisp->release ();
Lpdispatch pdisp_msg = NULL;
tagVARIANT Phone,msg,empty;
PHONE.VT=VT_UI4;
phone.lval=0;//This value is the order of the input box in the form
MSG.VT=VT_UI4;
msg.lval=1;//This value is the order of the text box in the form
if ((Pformelem->item (phone,empty,&pdisp)!=S_OK) | | (Pformelem->item (msg,empty,&pdisp_msg)!=S_OK))
{
Pformelem->release ();
if (pdisp)
Pdisp->release ();
if (pdisp_msg)
Pdisp_msg->release ();
Return "4 send Failure";
}
ihtmlinputtextelement* Phoneelem=null;
ihtmltextareaelement* Msgelem;
if (!pdisp| |! PDISP_MSG)
Return "11 failure";
if (! Succeeded (Pdisp->queryinterface (iid_ihtmlinputtextelement, void**) &phoneelem) | | (! Succeeded (Pdisp_msg->queryinterface (Iid_ihtmltextareaelement, (void**) &msgelem)))
{
if (Phoneelem)
Phoneelem->release ();
if (Msgelem)
Msgelem->release ();
if (pdisp)
Pdisp->release ();
if (pdisp_msg)
Pdisp_msg->release ();
Return "5 send Failure";
}
Widestring s_phone,s_msg;
S_phone= "888888"
s_msg= "Hello";
Phoneelem->put_value (S_PHONE.C_BSTR ())/fill in
Msgelem->put_value (S_MSG.C_BSTR ())/fill in
Pformelem->submit ()/Submit
Phoneelem->release ();
Msgelem->release ();
Pdisp->release ();
Pdisp_msg->release ();
Pformelem->release ();
Return "Send Success";
}
}
Return "Send Failed";
}