creating a array in javascript

is this:

var arr = {};

the same as

var arr = new Array();

?

It is not the same.

var arr = {};

initializes an object. If you want an array:

var arr = [];

not exactly. var arr = []; is more like it.

No.

var arr = {}; // creates a new object with no properties

But

var arr = []; // creates a new blank array

var arr = {}; creates object

No, it's not: You're confusing array literals

var arr = []; // same as new Array()

with object literals

var obj = {}; // same as new Object()