add property to element js code example

Example 1: javascript change attribute

var element = document.getElementById("elemId");
element.setAttribute("attributeName", "value");

Example 2: 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 3: set attribute javascript

Element.setAttribute(name, value);

Example 4: add property to object javascript

let yourObject = {};

//Examples:
//Example 1
let yourKeyVariable = "yourKey";
yourObject[yourKeyVariable] = "yourValue";

//Example 2
yourObject["yourKey"] = "yourValue";

//Example 3
yourObject.yourKey = "yourValue";