Accessibility of HTMLB Controls 

Use

General Information

This page offers general information for application developers using HTMLB who want to make their Web applications accessible. For details see section Accessibility on the More Info page for the respective controls.

Most accessibility features are already provided by the central rendering engine of HTMLB. Therefore, application developers only have to add those features that cannot be provided by default.

As an application developer, keep in mind that you cannot affect page elements on the basis of HTML tags or attributes. The only interface to the HTMLB controls is the HTMLB programming interface -- the HTMLB attributes and methods for the respective controls.

Application developers cannot set the title attribute of elements in order to extend descriptions, they have to use the setTooltip method, instead.

They also cannot set the summary attribute of tables, they have to use the setSummary method provided by HTMLB.

Descriptions

The central HTMLB rendering engine already provides general descriptions for HTMLB controls, such as the type, the state, and on-screen text. Therefore, application developers only have to complement descriptions in case that users need more specific descriptions or instructions. The descriptions written by the application developers are added to the default descriptions that are provided by the central rendering mechanism.

A button description has to be extended if a button opens a new window.

In general, a description has to be extended if a button introduces an interaction that cannot be recognized by a blind user.

 

Accessibility Flag

Also note that the resulting description that is sent to the users depends on the state of the accessibility flag:

·        If the accessibility flag is set, the default description is extended by the description that the application developer provided.

·        If the flag is not set only the description that the application developer provided is sent to the user.

Keyboard Accessibility

As application developers cannot set HTML attributes directly, they do not have access to the tabIndex attribute of elements. Consequently, application developers cannot add elements to the accessibility hierarchy themselves in order to make them keyboard accessible.

Input Elements and Corresponding Labels

Input elements, such as checkboxes, dropdown listboxes, input fields, radiobuttons, and text edit controls need to be connected to a label, so that screen readers recognize the association of the label with the input element. Use the HTMLB label control for this purpose (use method setLabelFor for identifying the corresponding control).

The connection between a label and its corresponding input element also simplifies the interaction with the element when using the keyboard or mouse.

References

·        SAP Portals Accessibility Guidelines

·        API Java Docs