Most Keyman Desktop keyboards can be compiled for KeymanWeb without modification. However, there are a few platform differences that it is important to be aware of, and a few differences in the supported Keyman Keyboard Language features between Keyman Desktop and KeymanWeb. The table below details the differences.
| Feature | Keyman Desktop | KeymanWeb | Notes |
|---|---|---|---|
| Basic features | |||
| Mnemonic layouts | Supported | Limited support | Mnemonic layouts are supported in KeymanWeb but only a subset of European keyboards are currently supported. See the notes under 'Detect system keyboard layout' for more information. |
| call statement | Windows DLL | Javascript function | In Keyman Desktop, this calls into a Windows DLL as defined in the referenced store, whereas the KeymanWeb version calls a Javascript function which must be included with the &KMW_EmbedJS system store |
| notany statement | Supported | Compile Error | This feature may be supported in a future version of KeymanWeb |
| return statement | Supported | Compile Error | This feature may be supported in a future version of KeymanWeb |
| nul statement in context | Supported | Compile error | In KeymanWeb, nul would correspond to the beginning of the text field or run of text, rather than an empty context cache. This will be supported in a future version of KeymanWeb |
| Deadkeys within stores | Supported | Compile error | Deadkeys can be used in Keyman Desktop stores with the index() statement. In KeymanWeb, this produces a compiler error. This may be supported in a future version of KeymanWeb |
| index and context statements in context | Supported | Compile error | These may be supported in a future version of KeymanWeb |
| &bitmap system store | Supported | Ignored | |
| &hotkey system store | Supported | Ignored | |
| &language system store | Supported | Ignored | |
| &windowslanguages system store | Supported | Ignored | |
| KeymanWeb-only features | |||
| &KMW_EmbedJS system store | Ignored | Supported | |
| &KMW_RTL system store | Ignored | Supported | To support right-to-left in a Keyman Desktop keyboard, associate it with a right-to-left locale using the &Language system store |
| &KMW_Help system store &KMW_HelpFile system store |
Ignored | Supported | Custom on-screen keyboard help for Keyman Desktop can be implemented with the usage.htm file |
| Virtual Keys and Modifiers Keys | |||
| CAPS, NCAPS modifier states | Supported | Ignored | Ignoring caps lock state may lead to conflicting rules in KeymanWeb when using + [NCAPS K_*] and + [CAPS K_*], so these rules should be prefixed with $KeymanOnly:. |
| &capsononly, &capsalwaysoff, &shiftfreescaps system stores | Supported | Ignored | KeymanWeb does not modify the action of the Caps Lock key |
| LALT, RALT, LCTRL, RCTRL modifier states | Supported | Ignored | Rules with these modifier states will never be matched in KeymanWeb: most browsers do not distinguish between left and right ctrl/alt, so KeymanWeb never tries to support them. |
| Virtual character keys | Supported | Compile error | This feature may be supported in a future version of KeymanWeb |
| Virtual keys in mnemonic layouts | Supported | Compile error | This feature may be supported in a future version of KeymanWeb |
| Virtual key output | Works, unsupported | Compile error | Virtual key output works in Keyman Desktop but is not supported by Tavultesoft and is not recommended — it is the wrong way to solve a problem, in the majority of situations. KeymanWeb does not support virtual key output and there are no plans to support this in the future in KeymanWeb. |
| Detect system keyboard layout | Supported | Configurable | KeymanWeb cannot reliably determine the system keyboard layout in use in the browser. The basic assumption is a US English keyboard layout, but this can be overridden by an implementor to specify and alternative layout. If an implementor specifies the system keyboard layout correctly, both mnemonic and positional layouts will translate correctly. |
| Legacy features | |||
| Codepage-based keyboards | Supported | Compile Error | Non-Unicode keyboards are not supported in KeymanWeb |
| &OldCharPosMatching system store | Legacy | Ignored | This is a legacy feature for older Keyman Desktop keyboards. Keyboards using this feature should be updated to use Keyman 6 character position matching |
| switch statement | Not supported | Compile Error | The switch statement is deprecated and no longer works in Keyman Desktop. |
| fix and clearcontext statements | Supported | Compile Error | Context is always read from the active element with a KeymanWeb keyboard so clearing the cached context is not a logical action. These statements are deprecated. |
| &layout system store | Ignored | Ignored | This system store is deprecated |
| Compile targets | |||
| Lines with $KeymanOnly: prefix | Supported | Ignored | |
| Lines with $KeymanWeb: prefix | Ignored | Supported | |
| Lines with $Keyman: prefix | Supported | Supported | For historical reasons, KeymanWeb keyboards also process $Keyman:-prefixed lines. The $KeymanOnly: prefix is intended to resolve this issue. |
| Lines with $weaver:, $kmfl: prefixes | Ignored | Ignored | These compile targets are for Mac OS 9 and Linux |
