The best way to create a new array is with the array literal syntax ([]),
but the array constructor function is available too. If you pass a single
number value to the constructor function, you get an array fi lled with
that many undefi ned values.
var myArray = [];
var myFilledArray = new Array(4);
myFilledArray;
[undefi ned, undefi ned, undefi ned, undefi ned]
Properties
Like strings, arrays have one built-in property: length. This property is
equal to the number greater than the last index in the array. This is true
even if you skip some indices.
["a", 1, true, null].length;
4
var myArray = [];
myArray.length;
0
myArray[99] = 1;
1
myArray.length;
100
The new length of myArray is 100 even though it contains only one value
at index 99. All the other values are undefined.
but the array constructor function is available too. If you pass a single
number value to the constructor function, you get an array fi lled with
that many undefi ned values.
var myArray = [];
var myFilledArray = new Array(4);
myFilledArray;
[undefi ned, undefi ned, undefi ned, undefi ned]
Properties
Like strings, arrays have one built-in property: length. This property is
equal to the number greater than the last index in the array. This is true
even if you skip some indices.
["a", 1, true, null].length;
4
var myArray = [];
myArray.length;
0
myArray[99] = 1;
1
myArray.length;
100
The new length of myArray is 100 even though it contains only one value
at index 99. All the other values are undefined.
