The three fundamental ways of finding information are to use the Contents, Index and Find (Search) tabs or panes, which are available for most online help formats.
This displays the topics that are in the help. These can be arranged into books. In this help there are two books ("Basics" and "Reference"). The books can be opened and closed to show and hide the details. Books can be nested.
Books cannot be opened and closed in the Contents pane when using HTML help.
This displays a list of all the words and phrases that the author has defined as being index terms. When the user selects an entry, the appropriate topic appears. If one term applies to more than one topic, the user is presented with a dialogue box or list from which to make a selection. For example, click on "topics, finding".
A further refinement is to jump to a specific location in the topic. For example, select "graphic link".
An index pane is time-consuming to implement in HTML help and there can be only a 1:1 correspondence between an index entry and a help topic.
Do we need an index even though the Find tab provides full text searching? Yes. An index contains author-defined terms such as synonyms which don’t necessarily appear in the text.
This allows a user to search for a word or phrase that appears in the help.
A Find pane cannot be implemented in HTML help.