how to code multiple keys on keydown? (javascript)

Question

I'm trying to have each key, correspond to different images when pressed. (Ex: When "A" is pressed = image1 appears, When "S" is pressed = image2 appears, and so on.)

I was able to get the "S" Key to work, but not the A. I'm trying to do this for the whole row on the keyboard ("A","S","D","F","G","H","J","K","L")

*PS. Im still a beginner :)

This is my code:

<img src="images/giphy.gif" width="800" height="400" alt=""/>

<script>
  document.addEventListener("keydown", keyDownBody, false);

  function keyDownBody(e) {
    var keyCode = e.keyCode;
    if(keyCode==65) {
      myFunction();
    }
  }

function myFunction() {
var x = document.createElement("IMG");
x.setAttribute("src", "images/giphy1.gif")
x.setAttribute("width", "800");
x.setAttribute("height", "400");
x.setAttribute("alt", "The Pulpit Rock");
document.body.appendChild(x);
}

function keyDownBody(e) {
    var keyCode = e.keyCode;
    if(keyCode==83) {
      myFunction();
    }
  }

function myFunction() {
var x = document.createElement("IMG");
x.setAttribute("src", "images/sun.gif")
x.setAttribute("width", "800");
x.setAttribute("height", "400");
x.setAttribute("alt", "The Pulpit Rock");
document.body.appendChild(x);
}
</script>

better to pass the value of keyCode to myFunction and stored image into object where properties would be keyCode and value would be image src — Mahi
– Mahi, Commented Dec 5, 2016 at 19:37
@Mahi Why are you downvoting and criticizing all answers, instead of just writing your own? — Duncan Lukkenaer
– Duncan Lukkenaer, Commented Dec 5, 2016 at 19:48

Duncan Lukkenaer · Accepted Answer · 2016-12-05 20:10:16Z

You have declared the same function multiple times. You could merge them to make it work, and also make your code more readable. An example:

document.addEventListener("keydown", keyDownBody, false);

function keyDownBody(e) {
  var keyCode = e.keyCode;
  switch (keyCode) {
    case 65:
        loadImage("images/giphy1.gif", "The Pulpit Rock");
        break;
    case 83:
        loadImage("images/sun.gif", "The Pulpit Rock");
        break;

    // Etc.
  }
}

function loadImage(uri, alt) {
    var x = document.createElement("IMG");
    x.setAttribute("src", uri)
    x.setAttribute("width", "800");
    x.setAttribute("height", "400");
    x.setAttribute("alt", alt);
    document.body.appendChild(x);
}

This way you can add as many keys as you wish.

Alternatively, you could load the images dynamically if you put them in an array:

var images = [{
      uri: 'images/giphy1.gif',
      alt: 'A',
    }, {
      uri: 'images/sun.gif',
      alt: 'Some text',
    }, 
    // Etc.
];

function keyDownBody(e) {
  var keyCode = e.keyCode;

  var index = keyCode - 65;
  if (typeof images[index] !== 'undefined')
  {
    var image = images[index];
    loadImage(image.uri, image.alt);
  }
}

score 2 · Accepted Answer · 2016-12-05 19:47:55Z

2

var keys_to_div = [];
keys_to_div[65] = "1"; // A key
keys_to_div[66] = "2"; // B key

window.onkeydown = function(e) {
    if (keys_to_div[e.keyCode])
	document.getElementById(keys_to_div[e.keyCode]).style.display = "block";
}

window.onkeyup = function(e) {
    if (keys_to_div[e.keyCode])
	document.getElementById(keys_to_div[e.keyCode]).style.display = "none";
}

img {
  width: 50px;
  height: 50px;
  display: none;
}

<img src="http://images4.fanpop.com/image/photos/22100000/The-letter-A-the-alphabet-22186936-2560-2560.jpg" id="1">
<img src="http://www.drodd.com/images15/letter-b23.gif" id="2">

edited Dec 5, 2016 at 19:47

answered Dec 5, 2016 at 19:41

user5797159

4 Comments

Mahi Over a year ago

your fiddle is broken + like this array length would be 66 and you are using only 2 variable. so use object instead

user5797159 Over a year ago

How is it broken?

Mahi Over a year ago

it's not displaying anything

user5797159 Over a year ago

@Mahi, You have to click on the area of the fiddle to focus it then press the keys that were set (A and B).

jafarbtech · Accepted Answer · 2016-12-05 19:36:38Z

0

Use same keydown EventListener to all the keys like

document.addEventListener("keydown", keyDownBody, false);

  function keyDownBody(e) {
    var keyCode = e.keyCode;
    if(keyCode==65) {
      myFunction("images/giphy1.gif");
    }
    else if(keyCode==83) {
      myFunction("images/sun.gif");
    }
  }

function myFunction(t) {
var x = document.createElement("IMG");
x.setAttribute("src", t)
x.setAttribute("width", "800");
x.setAttribute("height", "400");
x.setAttribute("alt", "The Pulpit Rock");
document.body.appendChild(x);
}

answered Dec 5, 2016 at 19:36

jafarbtech

7,0551 gold badge41 silver badges60 bronze badges

Comments

Diego Incerti · Accepted Answer · 2016-12-05 19:45:31Z

0

You just need to add more conditions

function keyDownBody(e) {
    var keyCode = e.keyCode;
    if(keyCode==83) {
      myFunction("images/giphy1.gif");
    }

    if(keyCode==85) {
      myFunction("images/giphy2.gif");
    }

    if(keyCode==87) {
      myFunction("images/giphy3.gif");
    }
  }

function myFunction(imageName) {
  var x = document.createElement("IMG");
  x.setAttribute("src", imageName)
  x.setAttribute("width", "800");
  x.setAttribute("height", "400");
  x.setAttribute("alt", "The Pulpit Rock");
  document.body.appendChild(x);
}

edited Dec 5, 2016 at 19:45

answered Dec 5, 2016 at 19:36

Diego Incerti

1367 bronze badges

2 Comments

Mahi Over a year ago

same image would be appeared every time .

Diego Incerti Over a year ago

Sorry for the incomplete answer. But you can pass any parameter to change the myFunction behavior.

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