Delete operator in JavaScript

The JavaScript delete operator removes a property from an object also removes an element from an array.

Delete Property

The JavaScript delete operator removes a property from an object; if no more references to the same property are held, it is eventually released automatically.
var Student = { firstname: "John", lastname: "Doe" } document.write(Student.firstname); delete Student.firstname; document.write(Student.firstname);
output
John undefined

Remove elmnts from Array

var ar = new Array (0, 1, 2, 3, 4,5); document.write (ar + "<br>"); delete ar[1]; document.write (ar);
output
0,1,2,3,4,5 0,,2,3,4,5