When a 3270 transaction is accessed by a Web client, CICS® can display
the output as an HTML form. Use the variants of the Web Terminal Translation
Application (DFHWBTTA, DFHWBTTB or DFHWBTTC) to provide Web clients with access
to applications that were originally designed to use the 3270 display system.
Attention: This topic contains Product-sensitive Programming Interface
and Associated Guidance Information.
An HTML form can be created from the output of a 3270 transaction in one
of two ways:
- For applications that use BMS, an HTML template is generated from a BMS
map, and stored in the template library. You can customize the generation
of the template. However, if the only changes you need to make to the generated
HTML can be accommodated in the heading or footing section, you do not need
to generate a template from the BMS map, as the map can be processed at execution
time to generate the HTML form.
- For applications that do not use BMS, the outbound 3270 data stream is
processed at execution time to generate the HTML form.
The Web Terminal Translation Application can be used to display the HTML
forms to a Web browser.
Note: 
The Web Terminal Translation Application
operates at HTTP/1.0 level. It does not make full use of the facilities available
in CICS Web
support (such as the
EXEC CICS WEB API), and so does not
provide compliance with the HTTP/1.1 specification. This means that:
- Requests from the Web client, and responses from the application, are
not checked against the HTTP protocol specification.
- CICS does
not provide HTTP/1.1 responses, in normal or error situations, even if the
client is at HTTP/1.1 level.

All three variants of the Web Terminal Translation Application support
non-conversational, conversational, and pseudoconversational transactions.
- DFHWBTTA and DFHWBTTB perform the translation between 3270 data streams
and HTML, and between templates generated from BMS maps and HTML. Use DFHWBTTA
if your HTML templates are 32767 bytes (32K) of data or smaller, and DFHWBTTB
if your HTML templates are larger than 32K. (Using DFHWBTTB for smaller HTML
templates incurs an unnecessary performance overhead.)
- DFHWBTTC performs the translation between BMS maps and HTML when no template
is generated. BMS maps used in this way must specify TERM=3270 or omit the
TERM parameter. DFHWBTTC supports HTML output of any length. Use DFHWBTTC
if you do not need to generate HTML templates.
DFHWBTTB and DFHWBTTC are aliases for DFHWBTTA; the same program (DFHWBTTA)
is invoked in each case. CICS uses the name by which the program is invoked to
determine which processing is needed.
DFHWBTTA, DFHWBTTB and DFHWBTTC generate HTML that conforms to the HTML
3.2 specification. If you use a Web browser that does not support HTML 3.2,
some functions may not work correctly.
HTML generated for terminals having
a pagesize which results in a field position greater than 4095 (x'FFF') might
not function correctly, particularly when using DFHWBTTC. The exception to
this is when using old style templates. (Old style templates are those generated
by DFHWBTLG from CICS TS 1.2 or CICS TS 1.3 before PTF UQ53534). Code has
been supplied to tolerate BMS sends of such templates when using DFHWBTTA
or DFHWBTTB, but not DFHWBTTC. 
You can create URIMAP definitions that specify DFHWBTTA, DFHWBTTB
or DFHWBTTC as the program to be invoked to process a request (PROGRAM attribute).
The method that the Web client uses to access the program is similar, but
the use of URIMAP definitions gives you an online administration facility
that can be used to prevent or redirect requests. When a URIMAP definition
is used, the use of an analyzer program is optional. URL path components for 3270 display applications explains
how to specify the URL path correctly when a URIMAP definition is used.
CICS Web
support does not provide support for partitions, logical devices codes, magnetic
slot readers, outboard formatting, or other hardware features. You can use
detectable fields with light pen support.