# Understanding No Keyboard Trap

## In brief

Goal
  Keyboard users don't get stuck.
What to do
  Ensure users always know how to navigate away from components.
Why it's important
  People who rely on the keyboard often have no other means to navigate.

## Intent of No Keyboard Trap

The intent of this Success Criterion is to ensure that that content does not "trap" keyboard focus within subsections of content on a Web page. This is a common problem when multiple formats are combined within a page and rendered using plug-ins or embedded applications.

There may be times when the functionality of the Web page restricts the focus to a subsection of the content, as long as the user knows how to leave that state and "untrap" the focus.

## Benefits of No Keyboard Trap

- People who rely on a keyboard or keyboard interface to use the Web including people who are blind and people with physical disabilities.

## Examples of No Keyboard Trap

A calendar widget
  A calendar widget allows users to add, remove or update items in their calendar using the keyboard. The controls in the widget are part of the tab order within the Web page, allowing users to tab through the controls in the widget as well as to any links or controls that follow.
A puzzle applet
  Once a user tabs into an applet, further tabs and other keystrokes are handled by the applet. Instructions describing the keystroke used to exit the applet are provided prior to the applet as well as within the applet itself.
A modal dialog box
  A Web application brings up a dialog box. At the bottom of the dialog are two buttons, Cancel and OK. When the dialog has been opened, focus is trapped within the dialog; tabbing from the last control in the dialog takes focus to the first control in the dialog. The dialog is dismissed by activating the Cancel button or the OK button.

## Resources for No Keyboard Trap

## Techniques for No Keyboard Trap

### Sufficient Techniques for No Keyboard Trap

- Ensuring that users are not trapped in content

### Additional Techniques (Advisory) for No Keyboard Trap

### Failures for No Keyboard Trap

- Failure of Success Criterion 2.1.2 and Conformance Requirement 5 due to combining multiple content formats in a way that traps users inside one format type