Robust keyboard shortcut handling using JavaScript

Question

What's the most robust way of creating a global keyboard shortcut handler for a Web application using JavaScript i.e. which event(s) should I handle and what should the event handler(s) be attached to?

I want something like the system in Gmail which can handle both single keypress shortcuts and also shortcuts with modifier keys e.g. Ctrl + B etc. The code has to work in IE 6 as well as modern browsers.

I have the Prototype framework available to use but not jQuery, so please, no jQuery-specific answers!

Answer 1

What I would do is attach onKeyUp events to the document.body. Then, in this event handler, I would use the Element.fire method to fire a custom event. Though this step is optional, it will help in decoupling the event handler from the action to be performed, and you can use the same custom-event handler from say an button click event.

$(document.body).observe("keyup", function() {
    if(/* key + modifier match */) {
        $(document.body).fire("myapp:mycoolevent");
    }
});

$(document.body).observe("myapp:mycoolevent", function() {
    // Handle event.
});

Later, to bind the same event to a button click:

$(button).observe("click", function() {
    $(document.body).fire("myapp:mycoolevent");
});

As far as handling modifier keys is concerned, check out this resource (very old, but still looks applicable) for more help.

Answer 2

The HotKey library available in the LivePipe controls package works with Prototype and is IE compatible.

http://livepipe.net/extra/hotkey

Answer 3

JimmyP posted this as a comment, but it deserves to be an answer for voting purposes.

http://www.openjs.com/scripts/events/keyboard_shortcuts/