First introduced with Windows 98, Microsoft HTML Help 1.x is currently the dominating help system in Microsoft Windows. It is primarily used to provide online help for applications running under Microsoft Windows; however, it is also used for other kinds of online help, as it provides an easy means to deliver an entire help system in a single consolidated file (.CHM file), which can be viewed off-line on a customers computer.

HTML Help 1.x has many advantages over its predecessor WinHelp, such as a redesigned, more user-friendly user interface, in the typical three-pane view containing a table of contents, an index, full-text search capability, and the ability to display HTML content.

Consider using Microsoft HTML Help 1.x if:


In order to be able to view Microsoft HTML Help 1.0 files, the customer’s computer must run any 32-bit or 64-bit version of Microsoft Windows, such as Windows 95, Windows 98, Windows Me, Windows NT 4.0, Windows 2000, Windows XP, Windows Vista, Windows Server 2003, or higher.

Note   Computers running Windows 95 or Windows NT 4.0 require Microsoft Internet Explorer 4.0 or higher and Microsoft HTML Help 1.3 or higher to be installed. These components are available from Microsoft as a redistributable.

Supported Languages

Microsoft HTML Help has great support for most languages through the use of codepages.

If you are building help files for a language other than the one of your operating system, be sure to choose the correct language from the Help Producer languages settings, so that Help Producer can select the proper codepage.

The codepages available and the language supported are listed below:

Codepage Languages supported (*)
Western European (1252) English, German, French, Spanish, and other West European languages.
Central European  (1250) Czech, Polish, Slovak, Romanian, Croatian, and other East European languages.
Cyrillic (1251) Russian, Bulgarian, Serbian, and other Cyrillic languages.
Japanese (932) Japanese
Korean (949) Korean
Chinese Simplified (936) Chinese
Chinese Traditional (950) Chinese
Thai (874) Thai
Greek (1253) Greek
Turkish (1254) Turkish
Hebrew (1255) Hebrew
Arabic (1256) Arabic
Baltic (1257) Lithuanian, Estonian, Latvian
Vietnamese (1258) Vietnamese

 (*) Certain languages have extended character sets, which may be absent from the codepage. For example, the language Urdu uses the Arabic codepage; however, some extended characters are missing from the codepage. Help Producer will automatically replace missing characters with a 'best-fit' character, which is a character that is the closest equivalent to the desired character.

Right-To-Left Language Restrictions

HTML Help 1.x has limited support for right-to-left (RTL) languages, such as Arabic or Hebrew. Paragraphs that have RTL and LTR text interspersed may not be displayed correctly in the table of contents or index.

Unicode Restrictions

Note   The following section applies only if you intend to mix codepages, i.e. you write a multilingual help file in two or more languages that are part of different codepages.

The Microsoft HTML Help 1.x viewer is only partially capable of handling Unicode, which can be problematic if you author help files that contain content written in more than one language.

To determine whether you can display two or more languages in the same help file, you need to understand some of the internals of the help viewer: The HTML Help viewer consists of two components, which are the navigation panes on the left and the topic display on the right. The topic display makes use of the Internet Explorer control, which is Unicode enabled, so you can display all languages at the same time, including mixed language content.

The navigation panes, which include the table of content, the index, and the full-text search, are not Unicode enabled; instead, codepages are used. Essentially, codepages restrict you to use only a certain set of characters at a time. For instance, the codepage 1252 (Western European) contains all ASCII characters, accented characters, umlauts, and other characters used in Western European countries, but it does not contain any symbols used in Chinese. By choosing the appropriate codepage, most languages can be displayed. To determine if you can use more than one language in the table of contents, index, or full-text search, you need to look at the codepage and find out if it contains the characters you will need. For instance, if you have a help file that mixes English and German, you can use codepage 1252 without any problems, since all characters of both languages can be represented in this codepage.

See Also

Output Types | Setting the Output Type | Setting the Project Language