How to check if a key has been pressed in javascript?

Question

I need to create a features: when a user held pressed a key, a function A is called. When a user release the button function B is called.

I need to make sure that first function runs only when the button is HELD. At the moment using chrome, when I keep pressed a button the function A is called repeatedly, and function B is running when release.

How is possible in java-script or jquery?

[keyup](https://developer.mozilla.org/en-US/docs/Web/Events/keyup) and [keydown](https://developer.mozilla.org/en-US/docs/Web/Events/keydown) event — Satpal, Aug 19 '14 at 07:52
You can write function for `keypress` and `keyup` events in jquery. — Jenz, Aug 19 '14 at 07:54
basically I need to develop something like show hide password as in the login windows in windows 8 — GibboK, Aug 19 '14 at 07:55
@GibboK http://stackoverflow.com/questions/1367700/whats-the-difference-between-keydown-and-keypress-in-net. Also not really sure why you're asking this type of question if you know how SO works (which you evidently do from your rep/badges). The answer is a quick google away/in the related answers on SO. — SubjectCurio, Aug 19 '14 at 07:58

score 2 · Accepted Answer · answered Aug 19 '14 at 07:54

2

$('#element').keyup(function() {
});

or

$('#element').bind('keyup', function() {
});

answered Aug 19 '14 at 07:54

Laurens Kling

2,221
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score 0 · Answer 2 · answered Aug 19 '14 at 07:54

0

jQuery's keyup should be what you're looking for: http://api.jquery.com/keyup/

You can bind it to input fields or the entire window, the latter probably being what you're looking for.

answered Aug 19 '14 at 07:54

Eugen Timm

744
6
13

score 0 · Answer 3 · answered Aug 19 '14 at 07:55

If your app should react in every part of html page use below code:

$(window).keydown(function(event){
    alert(event.keyCode);
});
$(window).keyup(function(event){
    alert(event.keyCode);
});

If only part of the window (like some div) use proper jquery expression like $("#myElement").keydown

How to check if a key has been pressed in javascript?

3 Answers3