IE 9<, Gecko, Opera
MDN / Property accessors / Bracket notation
MDN / String.prototype.charAt() / Description
charAt() attempts to convert index to an integer, while bracket notation does not, and directly uses index as a property name.
charAt() returns an empty string if index is out of range, while bracket notation returns undefined.
IE 9<, Gecko, Opera
MDN / Property accessors / Bracket notation
MDN / String.prototype.charAt() / Description