onMouseDown/Up must also support the Keyboard

Overview

The trio of onmousedown, onmouseup and onmousemove events are often used to create "drag and drop" user interface controls to implement features of a web page or application. However, these features need to be implemented through the keyboard as well, so that people who cannot use the mouse are able to access and use the features.

Benefit to People with Disabilities

  1. People with disabilities can use keyboard commands to access the same functions that can be achieved with the mouse.

Benefits to All Users

  1. All users will benefit from being able to use keyboard commands in addition to mouse actions.

Benefits to Developers

  1. Developers benefit by providing users with multiple ways to interact with their web resources.

HTML Markup Details

onmousedown, onmouseup and onmousemove attributes
The onmousedown, onmouseup and onmousemove event handlers are used to create "drag and drop" user interface elements. The equivalent functionality provided by the "drag and drop" user interface must also be provided through a keyboard interface.

Related Accessibility Requirements

Illinois Information Technology Accessibility Standards
13.1 Ensure that scripted functions are usable with assistive technologies.
13.2 Ensure that significant interactions can be performed with both keyboard and mouse.
Section 508
1194.21 (a) When software is designed to run on a system that has a keyboard, product functions shall be executable from a keyboard where the function itself or the result of performing a function can be discerned textually.
1194.21 (l) When electronic forms are used, the form shall allow people using assistive technology to access the information, field elements, and functionality required for completion and submission of the form, including all directions and cues.
1194.22 (l) When pages utilize scripting languages to display content, or to create interface elements, the information provided by the script shall be identified with functional text that can be read by assistive technology.
1194.22 (n) When electronic forms are designed to be completed on-line, the form shall allow people using assistive technology to access the information, field elements, and functionality required for completion and submission of the form, including all directions and cues.
W3C Web Content Accessibility Guidelines 2.0
2.1.1 Keyboard
2.1.2 No Keyboard Trap
2.1.3 Keyboard (No Exception)
Web Content Accessibility Guidelines (WCAG 1.0)
6.4 For scripts and applets, ensure that event handlers are input device-independent. [Priority 2]
8.1 Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies. [Priority 1 if functionality is important and not presented elsewhere, otherwise Priority 2]
9.3 For scripts, specify logical event handlers rather than device-dependent event handlers. [Priority 2]