Binding arrow keys in JS/jQuery

Question

How do I go about binding a function to left and right arrow keys in Javascript and/or jQuery? I looked at the js-hotkey plugin for jQuery (wraps the built-in bind function to add an argument to recognize specific keys), but it doesn't seem to support arrow keys.

Answer 1

document.onkeydown = function(e) {
    switch(e.which) {
        case 37: // left
        break;

        case 38: // up
        break;

        case 39: // right
        break;

        case 40: // down
        break;

        default: return; // exit this handler for other keys
    }
    e.preventDefault(); // prevent the default action (scroll / move caret)
};

If you need to support IE8, start the function body as e = e || window.event; switch(e.which || e.keyCode) {.

(edit 2020)
Note that KeyboardEvent.which is now deprecated. See this example using KeyboardEvent.key for a more modern solution to detect arrow keys.