Collection of data is called an array.
There are two types of an array.
Single dimension array
syntax:
var array_name=[n1, n2,...];
example
var marks=[10,20,30,40,50];
Calculate size of an array
console.log(marks.length)
Multi dimension array
syntax
var array_name=[
[n1, n2, ....],
[m1, m2, ....]
];
example
var person=[
["Rama", 20, "Almora"],
["Krishna", 20, "Nainital"]
];