function isMixedCase(s) {
                return Array.prototype.map.call(s, function mapper(c) {
                    return (c === c.toLowerCase());
                }).some(function checker(v, i, a) {
                    return (v !== a[0]);
                });
            }
Checks if a string is mixed case
@param {string} s The string
@returns {boolean} true if s is mixed case