var person = {
    firstName: "Penelope",
    lastName: "Barrymore",
    fullName: function () {
        ​// Notice  "this"  refers to an object
        console.log(this.firstName + " " + this.lastName);
    ​// We could have also written this:​
        console.log(person.firstName + " " + person.lastName);
    }
}

console.log(school.hasOwnProperty ("schoolName"));  // true because schoolName is an own property on the school object

// Prints false because the school object inherited the toString method from Object.prototype, therefore toString is not an own property of the school object.

console.log(school.hasOwnProperty ("toString"));  

var school = {schoolName:"MIT"};
console.log("schoolName" in school);  // true because schoolName is an own property on the school object

console.log("schoolType" in school);  // false because  because we did not define a schoolType property on the school object

// Prints true because the school object inherited the toString method from Object.prototype. 
console.log("toString" in school);  // true

var christmasList = {mike:"Book", jason:"sweater" }

delete christmasList.mike;  // deletes the mike property

Configurable Attribute

Enumerable

Writable:

datetime

createFromFormat

DateTime

$first_date = DateTime::createFromFormat('Y-m-d', "2020-12-23");
$second_date = DateTime::createFromFormat('Y-m-d', "2020-12-30");

diff()

DateTime

$difference_between_the_days = $second_date->diff($first_date)->format("%a");
	
echo $difference_between_the_days;

$Datetime_object = DateTime::createFromFormat('Y-m-d', "2020-12-23");

function hello() { alert('Hi there!'); }

setTimeout(hello, 5000)

setTimeout( function() { alert('Hi there!'); }, 5000 )

var family = ["mom", "dad", "mike", "jenny"]
var fstr = family.join();

fstr =  "mom,dad,mike,jenny"

 var parents = ["mom", "dad"]
  var children = ["mike", "jenny"]
  var family = parents.concat(children);

["mom", "dad", "mike", "jenny"]