Like in arrays we can add new elements by using array.push(item). How to do the same with objects? And can it be done inside the object? Like: 
var myObject={apple: "a", orange: "o"};
var anothObject = {lemon: "l", myObject};
Like in arrays we can add new elements by using array.push(item). How to do the same with objects? And can it be done inside the object? Like: 
var myObject={apple: "a", orange: "o"};
var anothObject = {lemon: "l", myObject};
 
    
    To copy all elements of one object to another object, use Object.assign:
var myObject = { apple: "a", orange: "o" };
var anothObject = Object.assign( { lemon: "l" }, myObject );
Or, more elegantly ES6 style using spread ... operator:
let myObject = { apple: "a", orange: "o" };
let anothObject = { lemon: "l", ...myObject };
 
    
    You could add some properties of an object simply like this :
obj = {a : "1", b : "2"};
myObj = {c: "3", d : "4"};
myObj.a = obj.a;
myObj.b = obj.b;
Update:
In that case just do this :
for(var prop in obj) myObj[prop] = obj[prop];
And to filter out the unwanted properties inside the loop body you could also do this :
for (var prop in obj) {
    if (obj.hasOwnProperty(prop)) {
        myObj[prop] = obj[prop];
    }
}
 
    
    You can use jQuery's extend function: http://api.jquery.com/jquery.extend/
var object1 = {
  apple: 0,
  banana: { weight: 52, price: 100 },
  cherry: 97
};
var object2 = {
  banana: { price: 200 },
  durian: 100
};
// Merge object2 into object1
$.extend( object1, object2 );
 
    
    A non-jquery option: you could iterate of the keys of the object to be merged.
var myObject={apple: "a", orange: "o"};
var anothObject = {lemon: "l"};
Object.keys(myObject).forEach(function(key) {
    anothObject[key] = myObject[key];
});
At the end of the loop anothObject is {lemon: "l", apple: "a", orange: "o"}
var myObject={apple: "a", orange: "o"};
myObject.lemon = 1; // myObject is now {apple: "a", orange: "o", lemon: 1}
 
    
    var addToObject = function (obj, key, value, index) {
// Create a temp object and index variable
var temp = {};
var i = 0;
// Loop through the original object
for (var prop in obj) {
    if (obj.hasOwnProperty(prop)) {
        // If the indexes match, add the new item
        if (i === index && key && value) {
            temp[key] = value;
        }
        // Add the current item in the loop to the temp obj
        temp[prop] = obj[prop];
        // Increase the count
        i++;
    }
}
// If no index, add to the end
if (!index && key && value) {
    temp[key] = value;
}
return temp;
};
 
    
    You can use jQuery.extend() function
var myObject={apple: "a", orange: "o"};
var anothObject = {lemon: "l"};
jQuery.extend(myObject, anothObject);
console.log(myObject);
