javascript - Keydown Simulation in Chrome fires normally but not the correct key

Question

I want to simulate keydown events on a given textarea element in an html page. Since I am using Chrome, I called initKeyboardEvent on my variable and I passed the keyCode I want to type into the textarea. Here is what I tried:

var keyEvent = document.createEvent('KeyboardEvent');
keyEvent.initKeyboardEvent('keydown', true, false, null, 0, false, 0, false, 77, 0);
inputNode.dispatchEvent(keyEvent);

In this code I'm typing the letter m however the textarea is only getting the keyCode 13 which is the Enter key. So, I tried an override code I saw online that sets the value to keyCodeVal, but with no success.

var keyEvent = document.createEvent('KeyboardEvent');
Object.defineProperty(keyEvent, 'keyCode', { 
                         get : function() {
                                 return this.keyCodeVal;
                         }
                        });
keyEvent.initKeyboardEvent('keydown', true, false, null, 0, false, 0, false, 77, 0);
keyEvent.keyCodeVal = 77;
inputNode.dispatchEvent(keyEvent);

Does anyone have an idea how to set the keyCode value?

Answer 1

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.