在keydown事件之后关注字段而不插入字符

Question

I have a shortcut key K . It should focus on my input, but I don't want it to insert the letter K when it focuses.

 $(document).keydown(function(event) { if (event.which == 75) { $('input').focus(); } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script> <input type="text"> 

Answer 1

You can use event.preventDefault() to stop the standard behaviour of the event. Note however that this will stop the letter K from being able to be typed in the input . To allow that you need to add a keydown handler to the input itself which stops the event propagation reaching the document . Try this:

 $(document).keydown(function(event) { if (event.which == 75) { event.preventDefault(); $('input').focus(); } }); $('input').keydown(function(e) { e.stopPropagation(); }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script> <input type="text"> 

Answer 2

This is another way:

At the time of keydown, if it is k and the input does not have focus then prevent the default behavior and give focus to the text field.

 $(document).keydown(function(event) { if (event.which == 75 && !$('input').is(":focus")) { event.preventDefault(); $('input').focus(); } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script> <input type="text"> 

Answer 3

If you want to abruptly stop the propagation, you can also use return false; :

 $(document).keydown(function(event) { if (event.which == 75) { $('input').focus(); return false; } }); $('input').keydown(function(e) { e.stopPropagation(); }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script> <input type="text"> 

Answer 4

var input = $('input');

$(document).on('keyup', function (e) {
  if(input.is(':focus')){
    return;
  }
  if (e.which == 75) {
        input.focus();
    }
});

1. Listen to the keyup event;
2. If the input is already focused, don't focus again.