vc++ web browser control catching javascript button click events

You need to sink the Web Browswer events using connection points in your code. This [^] may give some pointer to you.

Its a long way to get them all:
+ first you need a handler (as IDispatch better IDispatchEx)

#include <dispex.h>
class iDummy : public IDispatchEx
{
public: // IUnknown
  virtual HRESULT __stdcall QueryInterface(REFIID riid,void **ppv)
  {
    if(IID_IUnknown   ==riid) return *(IUnknown   **)ppv=this,AddRef();S_OK;
    if(IID_IDispatch  ==riid) return *(IDispatch  **)ppv=this,AddRef();S_OK;
    if(IID_IDispatchEx==riid) return *(IDispatchEx**)ppv=this,AddRef();S_OK;
    return E_NOINTERFACE;
  }
  virtual ULONG __stdcall    AddRef(){ return InterlockedIncrement(&_ref); }
  virtual ULONG __stdcall    Release(){ if(InterlockedDecrement(&_ref)) return _ref; delete this; return 0; }

public: // IDispatch
  virtual HRESULT __stdcall GetTypeInfoCount(UINT *pctinfo)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetTypeInfo(UINT iTInfo,LCID lcid,ITypeInfo **ppTInfo)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetIDsOfNames(REFIID riid,LPOLESTR *rgszNames,UINT cNames,LCID lcid,DISPID *rgDispId)
    { unsigned int i; for(i=0;(i<cNames) && (S_OK==GetDispID(rgszNames[i],0,rgDispId+i));i++); return i<cNames?DISP_E_MEMBERNOTFOUND:S_OK; }
  virtual HRESULT __stdcall Invoke(DISPID dispIdMember,REFIID riid,LCID lcid,WORD wFlags,DISPPARAMS *pDispParams,VARIANT *pVarResult,EXCEPINFO *pExcepInfo,UINT *puArgErr)
    { return InvokeEx(dispIdMember,lcid,wFlags,pDispParams,pVarResult,pExcepInfo,0); }

public: // IDispatchEx
  virtual HRESULT __stdcall GetDispID(BSTR bstrName,DWORD grfdex,DISPID *pid)
    { TRACE(__TEXT("call: %s\r\n"),bstrName); return E_NOTIMPL; }
  virtual HRESULT __stdcall InvokeEx(DISPID id,LCID lcid,WORD wFlags,DISPPARAMS *pdp,VARIANT *pvarRes,EXCEPINFO *pei,IServiceProvider *pspCaller)
    { if(0==id){ Beep(3000,100); }return E_NOTIMPL; }
  virtual HRESULT __stdcall DeleteMemberByName(BSTR bstrName,DWORD grfdex)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall DeleteMemberByDispID(DISPID id)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetMemberProperties(DISPID id,DWORD grfdexFetch,DWORD *pgrfdex)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetMemberName(DISPID id,BSTR *pbstrName)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetNextDispID(DWORD grfdex,DISPID id,DISPID *pid)
    { return E_NOTIMPL; }
  virtual HRESULT __stdcall GetNameSpaceParent(IUnknown **ppunk)
    { return E_NOTIMPL; }

public:
  iDummy(){ _ref=1; }
private:
  long  _ref;
};

+ next you have to walk all the HTML elements, even if the load is ready (examine the ready state of the web browser control):

  enum { childNodes, length, };

typedef void (*FNWALK)(IDispatch* node);

void WalkNode(IDispatch* node,BSTR* anames,FNWALK fn)
{
  VARIANT    ret1 = { VT_EMPTY, };
  VARIANT    ret2 = { VT_EMPTY, };
  VARIANT    ret3 = { VT_EMPTY, };
  VARIANT    ret4 = { VT_EMPTY, };
  
  fn(node);
  if(S_OK==InvokeName(node,anames[childNodes],ret1))
  {
    if(VT_DISPATCH==ret1.vt)
    {
      if(S_OK==InvokeName(ret1.pdispVal,anames[length],ret2))
      {
        if(VT_I4==ret2.vt)
        {
          wchar_t  num[32];
          ret3.vt = VT_I4;
          for(ret3.lVal=0;ret3.lVal<ret2.lVal;ret3.lVal++)
          {
            _itow_s(ret3.lVal,num,sizeof(num)/sizeof(num[0]),16);
            if(S_OK==InvokeName(ret1.pdispVal,num,ret4))
            {
              if(VT_DISPATCH==ret4.vt)
              {
                WalkNode(ret4.pdispVal,anames,fn);
              }
              VariantClear(&ret4);
            }
          }
        }
        VariantClear(&ret2);
      }
    }
    VariantClear(&ret1);
  }
}

void WalkDocument(IDispatch* doc,FNWALK fn)
{
  BSTR      anames[8];
  
  anames[childNodes] = ::SysAllocString(L"childNodes");
  anames[length] = ::SysAllocString(L"length");
  
  WalkNode(doc,anames,fn);
  for(int i=0;i<=length;i++) SysFreeString(anames[i]);
}

+ some helper functions needed as follows:

HRESULT InvokeName(IDispatch* node,BSTR name,VARIANT& ret)
{
  HRESULT  hr = E_FAIL;
  if(node)
  {
    DISPID      did = 0;
    DISPPARAMS  arg = { 0,0,0,0 };
    if(S_OK==node->GetIDsOfNames(IID_NULL,&name,1,0,&did))
    {
      hr = node->Invoke(did,IID_NULL,0,DISPATCH_PROPERTYGET,&arg,&ret,0,0);
    }
  }
  return hr;
}

HRESULT InvokeWithParams(IDispatch* node,BSTR name,VARIANT* aparam,const unsigned int nparam,VARIANT& ret)
{
  HRESULT  hr = E_FAIL;
  if(node)
  {
    DISPID      did = 0;
    DISPPARAMS  arg = { aparam,0,nparam,0 };
    if(S_OK==node->GetIDsOfNames(IID_NULL,&name,1,0,&did))
    {
      hr = node->Invoke(did,IID_NULL,0,(0<nparam?DISPATCH_PROPERTYPUT:DISPATCH_PROPERTYGET),&arg,&ret,0,0);
    }
  }
  return hr;
}

+ implement the walk function to replace the event handlers you want to replace:

void __fnWalk(IDispatch* node)
{
  BSTR      nodeName = L"nodeName";
  VARIANT    ret1 = { VT_EMPTY, };
  VARIANT    ret2 = { VT_EMPTY, };
  VARIANT    ret3 = { VT_EMPTY, };
  if(S_OK==InvokeName(node,nodeName,ret1))
  {
    if(VT_BSTR==ret1.vt)
    {
      TRACE(__TEXT("name: %s\r\n"),ret1.bstrVal);
      // if(!_wcsicmp(L"INPUT",ret1.bstrVal) || !_wcsicmp(L"BUTTON",ret1.bstrVal))
      {
        if(S_OK==InvokeName(node,L"OnClick",ret2))
        {
          if(VT_DISPATCH==ret2.vt)
          {
            VARIANT        a[8];
            unsigned int  n = 0;
            a[n].pdispVal = new iDummy;
            a[n].vt = VT_DISPATCH;
            ++n;
            if(S_OK==InvokeWithParams(node,L"OnClick",a,n,ret3))
            {
              VariantClear(&ret3);
            }
            while(0<n) VariantClear(a+(--n));
          }
          VariantClear(&ret2);
        }
      }
    }
    VariantClear(&ret1);
  }
  ++__walkdone;
}

+ finally the code you can use all of this:

  IDispatch*  doc = m_web.get_Document();
  if(doc)
  {
    __walkdone = 0;
    WalkDocument(doc,__fnWalk);
    doc->Release();
  }

Functions are tested and work with a simple form.
Good luck.

I have managed to get some of the implementation working. I am getting the name of the javascript function I want to listen to directly from the script file as in my implementation I will most of the time know this and for purposes of getting something working I have hard coded a goToNextSld function.



I get the dispid of the function I want to fire using

// specific predifined function I want to listen for which i will have in array later
            CComBSTR bstrMember1("GoToNextSld");
            pDisp->QueryInterface(IID_IHTMLDocument, (void**)&doc);
            hr = doc->get_Script(&p);

           
           
            p->GetIDsOfNames(IID_NULL, &bstrMember1, 1, LOCALE_SYSTEM_DEFAULT, &dispid); 

I managed to get Mbue code working by adding some more paramaters to the invoke with params method.

HRESULT InvokeWithParams(IDispatch* node,BSTR name,VARIANT* aparam,const unsigned int nparam,VARIANT& ret)
{
   HRESULT  hr = E_FAIL;
   EXCEPINFO excepinfo;
   UINT  puArgErr;
   DISPID      did = 0;
   DISPID      dispidNamed = DISPID_PROPERTYPUT;
   DISPPARAMS  arg = { aparam,0,nparam,0 };
   // These args are necessary otherwise your IDummy IDispatchEx will throw up 
   // error asking for more args
   arg.cArgs =1;
   arg.rgdispidNamedArgs = &dispidNamed;
   arg.cNamedArgs =1;
   arg.rgvarg[0].vt =VT_DISPATCH;
   arg.rgvarg[0].pdispVal = aparam->pdispVal;

   if(node)
   {
      if(S_OK==node->GetIDsOfNames(IID_NULL,&name,1,0,&did))
      {
        
         hr = node->Invoke(did,IID_NULL,LOCALE_SYSTEM_DEFAULT,(0<nparam?dispatch_propertyput:dispatch_propertyget),&arg,&ret,&excepinfo,&puargerr);>
      }
   }
   return hr;
}

Mbue's Code was adapted to only change a specific function but to actually do more than just beep is a problem. How do I implement the call back for the "GoToNextSld" function which i have the dispid for.

In the Idummy.h I tried:

virtual HRESULT __stdcall InvokeEx(DISPID id,LCID lcid,WORD wFlags,DISPPARAMS *pdp,VARIANT *pvarRes,EXCEPINFO *pei,IServiceProvider *pspCaller)
  {  Invoke(id,IID_NULL,0,
                       DISPATCH_METHOD,pdp,
                       0,0,0); return S_OK; }

can I overide this function completely in a IDummy.Cpp file? and Why am I receiving a stack overflow error

I am passing in

void RepWindow::setScriptProperty(IDispatch *p, BSTR bstrMember1, VARIANT ret1, VARIANT ret3)
{
   if(S_OK == InvokeName(p,bstrMember1,ret1))
   {
      if(VT_DISPATCH==ret1.vt)
      {
        // I have the function I want I have modified the IdispatchEx
         VARIANT        a[8];
         unsigned int  n = 0;
         a[n].pdispVal = new IDummy;
         a[n].vt = VT_DISPATCH;
         ++n;
         if(S_OK==InvokeWithParams(p,bstrMember1,a,n,ret3))
         {
            VariantClear(&ret3);
         }
         while(0<n)>      }
      VariantClear(&ret1);
   }

}

I am not doing a walk node and I am running this directly.... can you find see what I am doing wrong? I am not sure the dispid is getting passed in to the IdispatchEx function and I am not sure if I only should be doing this once. I want the current function to do what is doing at the moment. I want to add some extra functionality to it afterwards.

Thanks

Alttaf

Currently I am able to put and get properties of each of the buttons on my javascript page. I will store the variant arguments of the DISPATCH_PROPERTYGET Idispatch in a separate controller class. My question is how can I implement an event sink in the webroswer that will get the javascript function being called and its parameters? can anyone help?

You can assign javascript properties to the button of your choice by using

hr = p->Invoke(dispidChange, IID_NULL, 0, DISPATCH_PROPERTYPUTREF,&arg,&var,&excepInfo,&nArgErr);