Redefining an Existing Method : prototype « Object Oriented « JavaScript Tutorial

1. JavaScript Tutorial
2. Object Oriented
3. prototype

Function.prototype.toString = function () {
    return "Function code hidden";
};
function sayHi() {
    alert("hi");
}

alert(sayHi.toString());


Function.prototype.originalToString = Function.prototype.toString;

Function.prototype.toString = function () {
    if (this.originalToString().length > 100) {
        return "too long.";
    } else {
        return this.originalToString();
    }
};