How to check if value of input is changed?

Question

I'm trying to check if input was changed or not. Problem is - if i'll use this code:

trigger.keyup(function() {
    current_input = getSearchString();
    is_changed = (current_input != previous_input);
    previous_input = current_input;
});

This logic will break when user will press, for example "Q", after a short delay "E" (input value will be "QE" already) and release "Q" key first. previous_input will be set to "QE". User releases "E" key and script compares equal strings. So, when input actually did change, for my script it is not. Any idea how to fix this or is there any different way to do this (not with html5 event 'input')?

Would keydown help here?

tymeJV
– tymeJV

2013-04-26 13:20:41 +00:00
Commented Apr 26, 2013 at 13:20 — tymeJV
– tymeJV, Commented Apr 26, 2013 at 13:20
onchange tells you when it changed.

John Conde
– John Conde

2013-04-26 13:21:03 +00:00
Commented Apr 26, 2013 at 13:21 — John Conde
– John Conde, Commented Apr 26, 2013 at 13:21
onchange only fires when you lose focus

Ruben-J
– Ruben-J

2013-04-26 13:22:50 +00:00
Commented Apr 26, 2013 at 13:22 — Ruben-J
– Ruben-J, Commented Apr 26, 2013 at 13:22

Naftali · Accepted Answer · 2013-04-26 13:20:55Z

6

Use keydown instead of keyup, that way you are not reliant on whether or not the user releases the keys.

answered Apr 26, 2013 at 13:20

Naftali

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2 Comments

UnstableFractal Over a year ago

Ah, i've got confused because this part is combined with other logic in my script. Yeah, that'll completely solve my problem, thanks :)

Naftali Over a year ago

No problem @smsteel Happy to help! ^_^

techfoobar · Accepted Answer · 2013-04-26 13:25:22Z

0

Depending on key events alone is not a reliable mechanism. For example: what is user pastes text from the clipboard, or if he drags and drops text into the textbox (yes, dnd works for textboxes).

To account for all possible channels, you can use the textchanged event. Details here: http://zurb.com/playground/jquery-text-change-custom-event

$('#selector').bind('textchange', function (e, prevText) {
    // do your stuff here
});

answered Apr 26, 2013 at 13:25

techfoobar

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10 Comments

Naftali Over a year ago

Hmmmm then you can just listen to both change and keydown, no real need to add a plugin for it...

techfoobar Over a year ago

@Neal - Wrong! change won't fire for text inputs unless you press enter or lose focus.

Naftali Over a year ago

Right! Here you go: jsfiddle.net/maniator/7skY7 :-) it shows what was pasted into the input :-) All without an extra plugin (Here is the reason for the timeout: stackoverflow.com/questions/2055224/…)

techfoobar Over a year ago

@Neal - paste solves it to a large extent, yes (wont work in opera & older versions of safari - but will work on any decent new browser). Still it won't work if the user drags and drops text into the input.

rlemon Over a year ago

I think the real comment here should be about bind() being used. jQuery team suggests we use .on for this in recent versions (actually for a while now)

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