Sorry I am not exactly sure what are you looking for here. If you are looking at just finding keywords on a web page then most browsers will have a find function in built for example CTRL + F.
If this not what you are looking for please can you provide a little more information on what you are trying to achieve.
Most search boxes in the web sites themselves just use a search engine like Google and tack on the "site:" param. Like to search LoveHKFilm.com you would type this is google
keyword site:lovehkfilm.com. A concrete example:
Shu Qi site:lovehkfilm.com
Most engines support that syntax. DuckDuckGo will work with the same search line.