Keyboard-fu (also referred to as kfu in short) lets you assign arbitrary javascript to be executed for particular keystrokes. You are provided an API for various browser related actions from scrolling the page you are viewing to moving tabs, undo close tabs etc. You may mix and match these API functions and top it up with any arbitrary javascript to make your magic come true.
For example, you could have a single keystroke that only works on twitter.com
(yes, kfu supports a simple and powerful filtering mechanism), hitting which,
may aggregate all the youtube video links you have in your timeline and open
them up in individual tabs. Or, you could have a hotkey that works only on
youtube.com/v/* which would like/unlike the video you are watching. The
possibilities are endless.
In the options page, you can see the currently available hotkeys to the left of the page. Click on one of them to view/edit it. There is also a Add new hotkey at the bottom of that list to add a new hotkey.
When you are editing a hotkey, click on the Start Capture button and hit the
keys you want to have this hotkey to trigger. For example, if you hit the keys
abcd while capture is on, they will be recorded and appear in the field next
to the capture button. To invoke the javascript code associated with this
hotkey, you have to hit the keys a, b, c, d in that order as you did
the recording and do that a bit quickly. When you hit d the code associated
with this hotkey will run in the current page. Try it out, put the following
code in the code field and save it.
alert('yay! fu rocks!');
Now go to any webpage, say instapaper.com and hit the key(s) you have assigned to this hotkey. You should see the alert you put in the code appear. This is pretty much the basics of what you need to know to create simple hotkeys.
The way the filters work might seem tricky at first, but bear with me, it is the best combination of simplicity and power I could gather. Once you get the gist of it, you can easily create hotkeys that work on certain pages and don't on some other pages.
First off, there are two sets of filters for each hotkey. The local filters and the global filters. Local filters are local to the hotkey in which they are defined, but global hotkeys are common to all hotkeys. You can view/edit global hotkeys by clicking on Global Filters in the left side of the options page. Similarly, local filters can be configured for each hotkey in the hotkey editing form.
Now, when you open a webpage in chrome, Keyboard-fu goes through all the defined hotkeys and decides whether they apply on the page you are viewing or not. The way this is done is quite simple. For each hotkey, we create a master filter list as the following
Master filters list = Local filters list + Global filters list
Using this master filters list, we iterate over each filter and check if the
URL of the page you are viewing matches the filter and stop at the first match.
If this matched filter starts with a -, then the hotkey is not loaded,
else it is loaded. If none of the filters match the url you are viewing, the
hotkey is not loaded. This is why it is recommended to add a match all
filter, i.e., * as the last item in the global filters.
Also, note that when matching a filter with the url, a leading - if any, will
be stripped off before doing a match check.
In the javascript you write in the code field for each hotkey, you are given access to a simple yet powerful API to enable performing certain actions. You can know more about the API available by clicking the API Documentation item in the left side of the options page. The API is still evolving and does not have everything under the sky. If you think something could be added to the API, please let me know.
In addition of the API provided by Keyboard-fu, jQuery 1.5.1 is also available for these code snippets. You may use this to do all sorts of DOM manipulations or various ajax calls etc. Oh, and you don't need to wrap your code in the jQuery's ready event, if you're wondering, because by the time the hotkeys are loaded, the ready event will have fired.
- Opening options page through API opens a new tab with options, even if an options tab is already open.
history.backandhistory.forwarddon't integrate with the native back/forward buttons, sometimes.
There are a few limitations on what you could achieve with Keyboard-fu. The reason for these is sometimes the limits imposed by chrome's extension API, or a lack of knowledge in me, or just plain oversight.
- Hotkeys don't work on chrome extension pages and the webstore. This is a security limitation imposed by Google
- They also don't work on special chrome pages like the start page, extensions page etc.
- Some API functions may behave weirdly when operating with multiple windows. If you face any such issue, please let me know.
- If you configured a hotkey and the webpage you open also uses the same
hotkey, both will be fired when you hit the key. This is because I couldn't
figure out a way to detect if the webpage is handling a particular key. The
only way around this currently, is to add that webpage as a negative filter
(with a
-in the front) to that hotkey.
I am Shrikant Sharat, from Mumbai. The best way to get in touch with me is via email (self@sharats.me) or twitter (@sharat87).
Also, don't forget to rate the extension :)
Keyboard-fu is released with the MIT license.
The source code is hosted on github. Clone it and send a pull request to contribute. If you're making a fairly large change to the project, I'd prefer if you open an issue on github first, so we can discuss the right way to accomplish what you want.
by Shrikant Sharat Kandula (@sharat87)