javascript add an attribute to an object code example

Example 1: how to add property to object in javascript

var data = {
    'PropertyA': 1,
    'PropertyB': 2,
    'PropertyC': 3
};

data["PropertyD"] = 4;

// dialog box with 4 in it
alert(data.PropertyD);
alert(data["PropertyD"]);

Example 2: how to add field to object in js

// original object { key1: "a", key2: "b"}
var obj = {
    key1: "a",
    key2: "b"
};

// adding new filed - you can use 2 ways
obj.key3 = "c"; // static
// or
obj["key3"] = "c"; // dynamic - 'key3' can be a variable
console.log(obj) // {key1: "a", key2: "b", key3: "c" }