addEventListener不在按键上触发

Question

I'm trying to add custom keys to trigger events. I can get the keyup and the keydown events to work but for some reason the keypress event isn't working. I have seen many duplicates to these but most is in jquery.

In addition, in researching this, I came across the documentation that states that keyCode is deprecated and key should be used instead. However if I write

if (event.key === 74)

the code doesn't work

The code below is a simple example of what i'm trying to do.

 window.addEventListener('keypress', function(event) { if (event.keyCode === 74) { console.log('Show me'); } }); 

Answer 1

Your code works just fine (assuming you are entering a capital J ).

If you also want to check against a lowercase J , the keyCode would be 106 :

 window.addEventListener('keypress', function(event) { if (event.keyCode === 74 || event.keyCode === 106) { console.log('Show me'); } }); 

Answer 2

The difference is in the capital and small j. You are using code for capital j only

 window.addEventListener('keypress', function(event) { console.log(event.keyCode) if (event.keyCode === 74 || event.keyCode === 106) { console.log('Show me'); } }); 

Answer 3

You need to use the even.which when you check for J(74):

 window.addEventListener('keypress', function(event) { if (event.which === 74) { console.log('Show me'); } }); 

Answer 4

You can use key down instead, this will catch both upper and lower case j .

 window.addEventListener('keydown', function(event) { if (event.keyCode === 74) { console.log('Show me'); } });