Mastering JavaScript

Chapter 3
You have to use the array literal syntax if you want to initialize an array with a single
element and the element happens to be a number. If you pass a single number value
to the Array() constructor or function, JavaScript considers this parameter as the
length of the array, not as a single element:
var arr = [10];
var arr = Array(10); // Creates an array with no element, but with
arr.length set to 10
// The above code is equivalent to
var arr = [];
arr.length = 10;
JavaScript does not have an explicit array data type. However, you can use the
predefined Array object and its methods to work with arrays in your applications.
The Array object has methods to manipulate arrays in various ways, such as joining,
reversing, and sorting them. It has a property to determine the array length and
other properties for use with regular expressions.
You can populate an array by assigning values to its elements:
var days = [];
days[0] = "Sunday";
days[1] = "Monday";
You can also populate an array when you create it:
var arr_generic = new Array("A String", myCustomValue, 3.14);
var fruits = ["Mango", "Apple", "Orange"]
In most languages, the elements of an array are all required to be of the same type.
JavaScript allows an array to contain any type of values:
var arr = [
'string', 42.0, true, false, null, undefined,
['sub', 'array'], {object: true}, NaN
];
You can refer to elements of an Array using the element's index number. For
example, suppose you define the following array:
var days = ["Sunday", "Monday", "Tuesday"]
You then refer to the first element of the array as colors[0] and the second element
of the array as colors[1]. The index of the elements starts with 0.
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