nsresult result = aContent->QueryInterface(kIFormControlIID, (void**)&formControl);
nsresult result = aContent->QueryInterface(NS_GET_IID(nsIFormControl), (void**)&formControl);
void SetForm(nsIHTMLContent* aContent, nsIDOMHTMLFormElement* aForm){  nsIFormControl* formControl = nsnull;  nsresult result = aContent->QueryInterface(kIFormControlIID, (void**)&formControl);  if ((NS_OK == result) && formControl) {    formControl->SetForm(aForm);    NS_RELEASE(formControl);  }}