Keybindings, or keyboard shortcuts, undoubtedly increase usability, accessibility, and speed for the seasoned user - yet they are very seldom seen on the web. There are several reasons for this, some of which are outlined below.
UPDATE 2007-08-10:
Some specs: in the test, we listen for the "keydown" -event, read the keycode + modifiers, and try to cancel the event (to prevent the browser default). We also cancel "keyup" and "keypress" - this will prevent more side effects in some browsers. The canceling code is as follows:
function cancelEvent(e) { // try to prevent side effects (browser defaults) e = e || window.event; e.cancelBubble = true; e.returnValue = false; if (e.stopPropagation) e.stopPropagation(); if (e.preventDefault) e.preventDefault(); return false; }
Modern browsers do provide built-in ways to navigate web-pages with the keyboard, but usually you have to use multiple keystrokes to get to a link or button, before you can 'click' it - and although some browsers actually assign keybindings automatically, the browser simply can not know what would be a good keybinding for a specific function. And even worse: if the page changes, the keybindings might change - and they probably will.
This is of course unacceptable for web applications - imagine a secretary using a word-processor with keybindings that might change depending on the content of the document...
The problem with keybindings on the web is mostly a multiple platform problem; your users might be using one of several operation systems, with different utility-applications installed, running various browsers, and using different keyboard layouts. Some things to consider:
The operating system capture some key-combinations before they even reach the browser. Which key-combinations depends on the operating system - like Ctrl-Alt-Delete on windows.
Many utility-applications also capture key-combinations; for instance my Lenovo pops up a password manager when I press Ctrl-F2, and Ctrl-Alt-F12 opens the Intel Graphics Media driver configuration window.
The browser has built in keybindings. Some browsers allow many to be overridden, other browsers do not - and the keybindings vary between browsers. Some of the built-in keybindings still come trough so that your application can react, but they also cause some side-effect, like opening a new browser window.
Some keys vary between operating systems (and hardware platforms), especially 'meta' or control keys; windows uses Ctrl, where mac uses Command (although mac keyboards do have a Ctrl -key as well), and the recommended keybindings for common actions might vary.
US keyboard layouts differ from Finnish, which differ from French (for instance) - some keybindings might be awkward or impossible for someone using a different layout. Semi-colon (;) was bound to zoom-out in one application - but I have to press Shift to get that character, and the application did not expect shift to be pressed, so I could not zoom out using the keyboard. Much in the same way, many users might find Ctrl-Å difficult... Another example: forward-slash is convenient on US keyboards, but requires Shift-7 on Finnish keyboards.
Keybinding compatiblity chart for typical Windows browsers
Keybinding support for the most common Windows-based web browsers is summarized in the following table. Tested browsers were Firefox 2, Internet Explorer 7 and Opera 9.
