#### 14.8.5 Including heading letters in the index

You can include individual letters of the alphabet as headings to introduce each alphabetic section of the index. You can also include letters of the alphabet across the top of the page, each with a link to the corresponding heading letter within the index.

Heading letters as separators

To include heading letters to introduce each alphabetic section of the index:

    [Index]
    ; UseIndexLetters = Yes (default, insert alphabetics) or No
    UseIndexLetters = Yes
    ; IndexLetterSymbol = text to use, or blank to omit
    IndexLetterSymbol = Sym
    ; IndexLetterNumber = text to use, or blank to omit
    IndexLetterNumber = Num
    ; IndexLettersFormat = format to use for index alphabet headings
    IndexLettersFormat = IndexLetters
    ; IndexLetterPrefix = prefix to use for anchors for jumps to
    ; index heading letters
    IndexLetterPrefix = ixlet

When UseIndexLetters=Yes, DITA2Go inserts, as a heading, a letter of the alphabet at the beginning of each section of the index where entries start with that letter.

By default, heading characters are included for entries that start with a digit or with a non-alphanumeric character: for digits, the default heading is Num; and for non-alphanumeric characters, the default heading is Sym. You can change these headings. If you specify a sort order that ignores digits or symbols, you can set IndexLetterNumber or IndexLetterSymbol to blank. See §16.5.8 Customizing index sort order.

Heading letters at top of page

To include a row of letters across the top of each index page, linking to the heading letters:

    [Index]
    ; UseIndexTopLetters = Yes (default for RTF; for HTML, default only if
    ; IndexNavType=HTML: top-of-page alphabetics that link to heading
    ; letters) or No
    UseIndexTopLetters = Yes
    ; IndexTopLettersFormat = format to use for top-of-page alphabet
    IndexTopLettersFormat = IndexTopLetters

When UseIndexTopLetters=Yes, DITA2Go writes the alphabet across the top of the index page. Each letter is an active link to the same heading letter in the body of the index, unless there are no entries that begin with that letter.

For HTML, UseIndexTopLetters is effective only when IndexNavType=HTML; see §14.8.6.1 Choosing the type of index to generate for HTML.

Previous Topic: 14.8.4 Configuring index references

Next Topic: 14.8.6 Configuring index features for HTML output

Parent Topic: 14.8 Producing an index

Sibling Topics:

14.8.1 Specifying output formats for the index

14.8.2 Overriding formats for index entries and references

14.8.3 Configuring see and see-also index entries

14.8.4 Configuring index references

14.8.6 Configuring index features for HTML output