Add Character Codes from Keyboard Listeners as a javascript til.

Author: jbranchaud

README.md

@@ -34,6 +34,10 @@ smart people at [Hashrocket](http://hashrocket.com/).
 
 - [Not So Random](go/not-so-random.md)
 
+## javascript
+
+- [Character Codes from Keyboard Listeners](javascript/character-codes-from-keyboard-listeners.md)
+
 ### postgres
 
 - [Timestamp Functions](postgres/timestamp-functions.md)

javascript/character-codes-from-keyboard-listeners.md

@@ -0,0 +1,31 @@
+# Character Codes from Keyboard Listeners
+
+If I create the following keyboard event listeners for `keydown`,
+`keypress`, and `keyup`:
+
+```javascript
+window.addEventListener('keydown', function(e) { console.log("Keydown: " + e.charCode + ", " + e.keyCode); });
+window.addEventListener('keypress', function(e) { console.log("Keypress: " + e.charCode + ", " + e.keyCode); });
+window.addEventListener('keyup', function(e) { console.log("Keyup: " + e.charCode + ", " + e.keyCode); });
+```
+
+and then I press `A`, my browser console will read the following:
+
+```
+Keydown: 0, 65
+Keypress: 65, 65
+Keyup: 0, 65
+```
+
+and if I then press `a`, my browser console will read:
+
+```
+Keydown: 0, 65
+Keypress: 97, 97
+Keyup: 0, 65
+```
+
+The `keypress` event seems to be the way to go. Regardless, there seems to
+be quite a bit of [incompatibility and lack of
+support](https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent#Browser_compatibility)
+across browsers for various aspects of the keyboard events.