Keydown Simulation in Chrome fires normally but not the correct key

Orwellophile's solution does work.

• First: 'keyCode', 'charCode' and 'which' is readonly in Safari and IE9+ (at least).
• Second: initKeyboardEvent is kind of messy. All browsers implement it in a different way. Even in webkit's there are several different implementation of initKeyboardEvent. And there is no "good" way to initKeyboardEvent in Opera.
• Third: initKeyboardEvent is deprecated. You need to use initKeyEvent or KeyboardEvent constructor.

Here I wrote a cross-browser initKeyboardEvent function (gist):

Example:

var a = window.crossBrowser_initKeyboardEvent("keypress", {"key": 1, "char": "!", shiftKey: true})
alert(a.type + " | " + a.key + " | " + a.char + " | " + a.shiftKey)

And here is my DOM Keyboard Event Level 3 polyfill with cross-browser KeyboardEvent constructor.

Example:

var a = new KeyboardEvent("keypress", {"key": 1, "char": "!", shiftKey: true})
alert(a.type + " | " + a.key + " | " + a.char + " | " + a.shiftKey)

Example 2

Example 3

Important Note 1: charCode, keyCode and which properties is deprecated. So neither my crossBrowser_initKeyboardEvent no KeyboardEvent constructor is absolutely guaranteed right values of that properties in some browsers. You can using properties "key" and "char" instead or edit my gist to force using initEvent in browsers with read-only charCode, keyCode and which properties.

Important Note 2: keypress event is deprecated and for now unsupported in my Keyboard Event Level 3 polyfill. That's mean that key and char properties in keypress event can have random values. I am working to fix that problem to backward compatibility.

So very very close...

You just needed to override the 'which' property. Here's some sample code:

Podium = {};
Podium.keydown = function(k) {
    var oEvent = document.createEvent('KeyboardEvent');

    // Chromium Hack
    Object.defineProperty(oEvent, 'keyCode', {
                get : function() {
                    return this.keyCodeVal;
                }
    });     
    Object.defineProperty(oEvent, 'which', {
                get : function() {
                    return this.keyCodeVal;
                }
    });     

    if (oEvent.initKeyboardEvent) {
        oEvent.initKeyboardEvent("keydown", true, true, document.defaultView, false, false, false, false, k, k);
    } else {
        oEvent.initKeyEvent("keydown", true, true, document.defaultView, false, false, false, false, k, 0);
    }

    oEvent.keyCodeVal = k;

    if (oEvent.keyCode !== k) {
        alert("keyCode mismatch " + oEvent.keyCode + "(" + oEvent.which + ")");
    }

    document.dispatchEvent(oEvent);
}

Sample usage:

Podium.keydown(65);

Note: this code is not designed to work in IE, Safari, or other browsers. Well, maybe with Firefox. YMMV.

In order to get @Orwellophile's script to work on Google Chrome 26.0.1410.65 (on Mac OS X 10.7.5, if that matters), I had to change one line: his script appears to have the paramaters of initKeyboardEvent in different order than the MDN documentation for initKeyboardEvent.

The changed line looks like this:

oEvent.initKeyboardEvent("keydown", true, true, document.defaultView, k, k, "", "", false, "");