function isAlphaNumeric( x ) {
	var len;
	var ch;
	var i;
	if ( !isString( x ) ) {
		return false;
	}
	len = x.length;
	if ( len === 0 ) {
		return false;
	}
	for ( i = 0; i < len; i++ ) {
		ch = x.charCodeAt( i );
		if (
			(ch < ZERO || ch > NINE) &&
			(ch < a || ch > z) &&
			(ch < A || ch > Z)
		) {
			return false;
		}
	}
	return true;
}
Tests whether a string contains only alphanumeric characters.

@param {*} x - value to test
@returns {boolean} boolean indicating if a string contains only alphanumeric characters

@example
var out = isAlphaNumeric( 'abc123def456' );
// returns true

@example
var out = isAlphaNumeric( '0xffffff' );
// returns true

@example
var out = isAlphaNumeric( '123' );
// returns true

@example
var out = isAlphaNumeric( '' );
// returns false

@example
var out = isAlphaNumeric( 123 );
// returns false