When you trap a keyboard event with any of the keyboard event handlers (onKeyUp, onKeyDown, or onKeyPress), the event object’s keyCode property contains the character value of the key that triggered the event. However, the value in keyCode is a character code (Unicode in Internet Explorer and ASCII in Navigator), not an alphanumeric character.
To do the conversion, you can use the JScript String method, ‘fromCharCode’. The JScript statement below is an example of how it’s done:
var charCode = String.fromCharCode(e.keyCode);
The keyCode property of e, the event that was trapped by the event handler, is sent to the String method ‘fromCharCode’. It converts the character code representation of the character to an alphanumeric character and assigns it to the variable ‘charCode.’