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csitol

Problem with Bind.("keydown") in jQuery 1.4.2

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in Developing jQuery Core • 12 years ago

I'm trying to implement the jquery.hotkeys.0.7.9 plugin. It's very nice since it allows me to specify complex key codes in english rather than numbers.

However, in 1.4.2 I've run into a problem. If I make four binds the function in a particular bind is called four times. If I make two binds that single bind is called twice. In 1.4.1 and 1.3.2 it works as expected, the function is called once.

Code snippet is:

            $(document).bind("keydown","ctrl+left",function(e){
                getRow('first', null);
                return false;
            });
            $(document).bind("keydown","left",function(e){
                getRow('prev', null);
                return false;
            });
            $(document).bind("keydown","right",function(e){
                getRow('next', null);
                return false;
            });
            $(document).bind("keydown","ctrl+right",function(e){
                getRow('last', null);
                return false;
            });

The getRow function gets a data row from a grid that is hidden. Everything works as expected. However, in 1.4.2 if I press the right arrow key the function getRow('next', null) will be called four times. If all I change is the version number in my <script> call (as follows) to 1.4.1 or 1.3.2 it works perfectly. Is this a change or a bug?

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>

Thank you!

Replies(12)

csitol

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

Further:

I stepped through the code in hotkeys. When they bind the "keydown" event they add data to the bind command, so you get something like this:

$(selector).bind("keydown","left",function(){//their function here});

For each "keydown" bind they create another one of these, so at the end I've got four of them using the example above; ctrl+left, left, right and ctrl+right.

In 1.4.1 and below you apparently look at the second param to determine if this is a unique bind. In 1.4.2 you don't.

I'm hoping someone there knows more about this than I do. However, since I'd like to stay current with jQuery and since I love it so much, I'm more than willing (I know I'm going to regret this) to dive into it and see what's changed.

Let me know.

jeresig

Re: Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

There were a number of problems with the old technique - either you wouldn't be able to unbind the handler after the fact or the handler would overwrite the old handler you bound, causing the old ones to no longer work. I suspect that they hotkeys plugin should probably be adapted to work with the new underlying event model.

Ok, so I just looked at the hotkeys plugin: That's some really frightening code. They don't use the special events system, at all, and instead override a bunch of jQuery methods. It's really no wonder that it's not working any more.

Unless someone else steps up I might just rewrite this plugin to use the new special event system as it would really benefit from it (using significantly less code and working correctly).

csitol

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

John,

Thanks for replying so quickly. I don't disagree. The plugin is a bit of a kludge. However, I've seen a lot of that trying to get around other problems. And, it fills a big need for those of us trying to write applications for others who are used to desktop keyboard handlers.

I know you've got plenty on your plate so I'll see if I can take a look at it and figure out what to do with special events.

You and your team have done a wonderful job with jQuery. Please keep it up!

jeresig

Re: Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

This seemed like a great case for using the special event system in jQuery so I rewrote the code:

http://github.com/jeresig/jquery.hotkeys

It's dramatically simpler now. It's not 100% identical to the hotkeys plugin (namely in that it no longer accepts an object as the second argument, input hotkeys are prevented by default, as explained in the README).

It also fixes the problem with keypress not working properly and even allows you to do key combos like "ctrl+shift" (with no additional keys). The revised code:

http://github.com/jeresig/jquery.hotkeys/blob/master/jquery.hotkeys.js

I haven't tested it much yet so feedback is appreciated.

csitol

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

Tremendous work! Thank you so much!

Oh, BTW, works as expected. Personally, I don't think skipping the events when in a text/select box is a problem. And, in regards to your comment about which browsers trap which keys automatically, I plan on allowing the user to choose their keys. I would recommend that all developers do the same. In my case I have some users from a previous lifetime who will, I'm sure, want to use F5, F6, F7, F8 for first, previous, next and last instead of the arrow keys since that's what they're used to. And, if they use a browser that traps certain keys (instead of FF) it gives them a way out.

By using English key codes it gives me a very easy way to translate what they want directly to code (no translation necessary!).

A huge benefit to what you've done, especially for us developers, is learning how something like this should work. So, you've given us a double benefit!

Thank you again!

jboesch

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

A little late, but I also wrote a full blown hotkeys/keystrokes plugin a few months ago that uses the special event API.

http://boedesign.com/blog/2009/12/30/keystrokes-for-jquery/
http://github.com/jboesch/Keystrokes

jeresig

Re: Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

Cool stuff! Sorry about the change to the special add/remove API in 1.4.2 - we really had to make the change right away with the modification to the event system or else make an even bigger change later on when we hit 1.5. The workaround is simple (if you want to temporarily support jQuery 1.4.0 and 1.4.1, that is):

add: function( handler ) {
var oldHandler;
if ( typeof handler === "function" ) {
oldHandler = handler;
return newHandler;
} else {
oldHandler = handler.handler;
handler.handler = newHandler;
}
function newHandler(){ /* stuff */ }
}

csitol

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

It's certainly nice to see multiple solutions to this problem. Especially for learning purposes! Thank you for taking the time to respond.

BTW, I also read Brandon's article but decided I needed more time to study it over. On first review it didn't answer my questions.

ray73864

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

Thanks for this jeresig, there's just one problem i have with this updated version... I need to be able to capture shortcut keys that aren't attached to an input box while the user is focused on the input box.

For our WebPOS at work, a staff member is currently (using the old version of this) able to press a function key while the focus is on a text box, mostly because the hotkeys are global across the site, so they could currently be on the parts list, which auto-focuses on the text box for choosing a part and then press F10 to go back to the vehicle list.

However using this new version of yours, i would lose all abilities to do that. In the old version of the program, by default it captured hotkeys even when focused on an input box, however if you didn't want that functionality for a particular hotkey, you simply passed a 'disableInInput' name with a value of 'true' it would turn off that feature.

Is there a chance you could recode it so that it supports that feature?

[code]

jQuery(document).bind('keydown.hotkeys', {combi: 'J', disableInInput: true}, 
function() { console.log('J was pressed') });

[/code]

ianian1

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

Oh what a great fix! Thanks.

ray73864, it says in the notes,

Hotkeys aren't tracked if you're inside of an input element (unless you explicitly bind the hotkey directly to the input).

lathan.bi..

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

ianian1, ray73864 didn't say that that worked, but that it would be nice if it did.

I have ajax tabs that load in pages to edit files, and I would like to bind to the ctrl+s EVEN in a textarea, but something in the new hotkeys plugin disables all other keydowns if you try to bind to a textarea.

I do not understand what is stopping the other keydowns in the textarea, but it would be very nice to be able to use that.

csitol

Re: Problem with Bind.("keydown") in jQuery 1.4.2

12 years ago

I made a slight change to John's code so that you can now add IncludeInput at the end of the key list. It looks something like this:

    $(document).bind("keydown","ctrl+s includeInput",function(e){
        cgGridMaintGrid_saveData(false);
        return false;
    });

If this is what you're looking for please email me at phil at cappgen.com. I'd be more than happy to send it to you. I've never added it to the code since John thought it wasn't a good change.

Regards,
Phil Mickelson

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