If your script just need to find a movie/person and download one page with information you will need to write code like this:
Result := SEARCH_STR

If you need to download and parse more than one page I recommend to define extra variables or an array of URLs that need to be downloaded. Code for 2 information pages will look like this:
 if CreditsURL = '' then
  Result := SEARCH_STR
 else
  Result := SecondPageURL;

You can also use the mode variable as an extra flag. This code is for 3 pages using mode variable:
 if (Mode > 1) AND  (PosterURL <> '') then
  Result := PosterURL
 else
 if CreditsURL <> '' then
  Result := CreditsURL
 else
  Result := SEARCH_STR;


If you download poster in a movie information script or a photo in a person information script than make sure URL to an image is passed after all other pages are retrieved!

The following actions have to be made in this function:
a. Determine what information does this page contain (search results, movie/person information, etc.) b. Set the mode variable (if script state changes from "searching" to "found") c. Parse HTML and set information fields d. Return an appropriate result

a. Determine what information does this page contain
It's pretty simple: You need to find a unique marker in HTML for each page type and do some parsing according to what you have found on this page. Ex.:
if Pos('<title>Movie</title>', HTML) > 0 then begin

b. Set the mode variable
Mode := 1;

c. Parse HTML and set information fields
ParseMovie(URL, HTML); //This is a helper procedure to make the code better readable.

d. Return an appropriate result
Result := 1; //script has finished its job

The part of the code that determines the type of the web-page and does the rest of the actions should look like this:
if Pos('<title>Movie</title>', HTML) > 0 then begin
 Mode := 1; //>0 – found field data
 ParseMovie(URL, HTML); //This is a helper procedure to make the code better
 Result := 1; //script has finished its job
end;

I recommend you to create a helper procedure to parse each page type. Ex.:
procedure ParseSearchResults(HTML : String); //parse search results
procedure ParseMovie(HTML : String); //parse main movie information
procedure ParseCredits(HTML : String); //parse movie credits

The whole ParsePage function should look like this:
function ParsePage(HTML : WideString; URL : String) : Cardinalbegin
 if Pos('<title>Search results</title>', HTML) > 0 then begin
  ParseSearchResults(HTML);
  Result := 2; //search results retrieved
end else
 if Pos('Nothing found', HTML) > 0 then
  Result := 0 //error (movie not found)
else
 if (Pos('<title>Movie</title>', HTML) > 0) then begin
  Mode := 1; //>0 – found field data
  ParseMovie(URL, HTML);
  Result := 1; //script has finished its job
end else
  Result := 0; //error (unknown page retrieved)
end;