Javascript String isUpper()

//PROTOTYPES//from  ww w. jav a 2 s  .c o m
String.prototype.isUpper = function () {
    var char = this[0];
    var rtn = false;
    if (char == char.toUpperCase()) rtn = true;
    return rtn;
}

String.prototype.isUpper = function () {
 return this.toUpperCase() == this;
}