Only those html documents which contain all of the terms entered will be returned. Depending on how broad or narrow the user wishes the search to be, they can select either option. Selecting OR will broaden the search and selecting AND will narrow the search. Only one Boolean operator can be used at a time. Every document which contains any one of those words will be returned in the list of results.
Users can tell the search engine if they want a case sensitive or case insensitive search.
The default is for the search engine to disregard the case of the letters entered by the user.