i want to create a simple event handler for a game, here's my code
$(document).keydown(function(e){ switch(e.keyCode){ case 65: //left (a) console.log('left'); break; case 68: //right (d) console.log('right'); break; } }); the problem is that if i press and hold a key, after a little it triggers multiple times. how can i prevent this behaviour? i'm running my code on google chrome
This is key repeat. You can defeat it if you want to, by remembering that you already know the key is down:
// A map to remember in var keysdown = {}; // keydown handler $(document).keydown(function(e){ // Do we already know it's down? if (keysdown[e.keyCode]) { // Ignore it return; } // Remember it's down keysdown[e.keyCode] = true; // Do our thing switch(e.keyCode){ case 65: //left (a) console.log('left'); break; case 68: //right (d) console.log('right'); break; } }); // keyup handler $(document).keyup(function(e){ // Remove this key from the map delete keysdown[e.keyCode]; }); Side note: I think when you're using jQuery, e.which is the more reliable property, as it's normalized for you by jQuery.
var keyPressed = false; $(document).on('keydown', function(e) { var key; if (keyPressed === false) { keyPressed = true; key = String.fromCharCode(e.keyCode); //this is where you map your key if (key === 'X') { console.log(key); //or some other code } } $(this).on('keyup', function() { if (keyPressed === true) { keyPressed = false; console.log('Key no longer held down'); //or some other code } }); }); 
.keyup()would be the right choice 4 sure....keyupis part of the solution, but just switching fromkeydowntokeyupwould probably be unpopular with users.