javascript - jQuery KeydownKeyup only works every second time - Stack Overflow

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I have keyup/down events binded to the document. The Keydown will only fires every second time, without me knowing why. I tried many suggestions given on similar SO-Questions, but none of them works.

My Javascript:

$(document).on('keyup', function() {
    $('div').removeClass('bar');
});
$(document).on('keydown', function(e) {
    if(e.altKey) {
        $('div').addClass('bar');  // only every second hit will add the class
    }
});

This should point out the issue: /

I have keyup/down events binded to the document. The Keydown will only fires every second time, without me knowing why. I tried many suggestions given on similar SO-Questions, but none of them works.

My Javascript:

$(document).on('keyup', function() {
    $('div').removeClass('bar');
});
$(document).on('keydown', function(e) {
    if(e.altKey) {
        $('div').addClass('bar');  // only every second hit will add the class
    }
});

This should point out the issue: http://jsfiddle/6yxt53m9/1/

• javascript
• jquery

Share Improve this question Follow asked Sep 18, 2014 at 8:59 JonathanJonathan 2,07355 gold badges3131 silver badges5454 bronze badges 4

• Do you have to use the alt key? – artm Commented Sep 18, 2014 at 9:01
• Works the first time for me under ubuntu and chrome – Brewal Commented Sep 18, 2014 at 9:01
• Yes it must be the alt key – Jonathan Commented Sep 18, 2014 at 9:02
• I'm on Chrome at Mac, but this fiddle is working fin for me. – Sameera Thilakasiri Commented Sep 18, 2014 at 9:06

Add a ment  | 

3 Answers 3

Sorted by: Reset to default 7

You need to add return false; to the key press functions:

$(document).on('keyup', function() {
    $('div').removeClass('bar');
    return false;
});

$(document).on('keydown', function(e) {
    if(e.altKey) {
        $('div').addClass('bar');
    }
    return false;
});

Updated fiddle.

use

$(document).on('keyup', function(e) {
    $('div').removeClass('bar');
    e.preventDefault();
});

e.preventDefault(); will reset the input

Try this.

$(document).on('keydown', function(e) {
    e.preventDefault();
    if(e.altKey) {
        $('div').addClass('bar');  // only every second hit will add the class
    }
});

The reason is alt key occurs focus moving to button of "customize and control google chorome"

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