Why doesn't addEventListener fire on keypress?

A

Alexey Esin2016-01-26 17:22:12

JavaScript

Alexey Esin, 2016-01-26 17:22:12

//game.js
function init() {
var moveLeft = false;
var moveRight = false;
var player = document.getElementById("player");

addEventListener("keydown", function(event){
if(event.keycode == 37)
  moveLeft = true;
if(event.keycode == 39)
  moveRight == true;
});
addEventListener("keyup", function(event){
if(event.keycode == 37)
  moveLeft = false;
if(event.keycode == 39)
  moveRight == false;
});

if(moveLeft)
  alert("l");
if(moveRight)
  alert("r");
}

The code is included after loading the body

<body onload="init();">

<div class="mainframe">
  <div id="player"></div>
  <input type="button" id="add" value="add">
</div>

<script src="js/game.js"></script>

</body>

What's wrong with the code?
I saw somewhere that if you enter a function with brackets () into the arguments of addEventListener , then this will cause it to be immediately executed.
But does this rule apply to this kind of record ( function(event){}) ?
And is this the cause of the error?
There is nothing in the console.

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1 answer(s)

D

Dmitry Belyaev, 2016-01-26
@royal-gaben

First, what are you hanging the event on? to the window object?
Secondly, at the time of this code execution:

if(moveLeft)
  alert("l");
if(moveRight)
  alert("r");
}

events have not yet occurred, respectively, both if will be rejected