jquery - How to create a keyboard shortcut for an input button

Question

I am showing a bunch of pictures and each picture has its own HTML page. I have an input button that onclick will take you to the next link for the picture. However, I want to be able to use my keyboard arrows to go forward and back. I am new to coding and don't know if this is possible. Can I do this with HTML using the accesskey:

<input type="button" accesskey="?" value="Next Item">

Or do I need to use a JQuery plugin? If so, which one?

Answer 1

As zzzzBov explained, the HTML accesskey defines a key that will be trapped only when it is combined with the ALT key. That is why that is not useful for trapping any key alone.

But you have to take special care choosing the event to trap the cursor keys because Webkit has decided not to trap them with the keypress event as it is not in the standard. At this moment the other 3 answers here use this keypress event and that is why they don't work in Google Chrome nor Safari, but if you change that to keydown they'll work on all browsers.

You can use this jQuery code to capture the keydown event of the left, right, up, and down arrow keys:

$(window).keydown(function(e) {
  switch (e.keyCode) {
    case 37: // left arrow key
    case 38: // up arrow key
      e.preventDefault(); // avoid browser scrolling due to pressed key
      // TODO: go to previous image
      return;
    case 39: // right arrow key
    case 40: // up arrow key
      e.preventDefault();
      // TODO: go to next image
      return;
  }
});

And in the following code snippet you can see and run a complete example in which images are swapped using the keys or the buttons.

var currentImage = 0;
var imagesArray = [
  'https://upload.wikimedia.org/wikipedia/commons/thumb/3/35/Tux.svg/150px-Tux.svg.png',
  'https://upload.wikimedia.org/wikipedia/commons/thumb/8/80/Wikipedia-logo-v2.svg/150px-Wikipedia-logo-v2.svg.png',
  'https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Git-logo.svg/150px-Git-logo.svg.png'
];

function hasPrev() {
  return currentImage > 0;
}

function hasNext() {
  return currentImage < imagesArray.length - 1;
}

function goToPrev(e) {
  e.preventDefault();
  if (!hasPrev())
    return;
  currentImage -= 1;
  updateScreen();
}

function goToNext(e) {
  e.preventDefault();
  if (!hasNext())
    return;
  currentImage += 1;
  updateScreen();
}

function updateScreen() {
  $('#imgMain').attr('src', imagesArray[currentImage]);
  $('#btnPrev').prop('disabled', !hasPrev());
  $('#btnNext').prop('disabled', !hasNext());
}

$(document).ready(function() {
  updateScreen();
  $('#btnPrev').click(goToPrev);
  $('#btnNext').click(goToNext);
});

var keyCodes = {
  left: 37,
  up: 38,
  right: 39,
  down: 40
};

$(window).keydown(function(e) {
  switch (e.keyCode) {
    case keyCodes.left:
    case keyCodes.up:
      goToPrev(e);
      return;
    case keyCodes.right:
    case keyCodes.down:
      goToNext(e);
      return;
  }
});

button:enabled kbd {
  color: green;
  font-weight: bold;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="btnPrev">
  Previous Image
  <br/>
  <small>(arrow keys: <kbd>left</kbd> or <kbd>up</kbd>)</small>
</button>
<button id="btnNext">
  Next Image
  <br/>
  <small>(arrow keys: <kbd>right</kbd> or <kbd>down</kbd>)</small>
</button>
<br/>
<img id="imgMain" src="">