Array splice()

splice() inserts items into the middle of an array. splice() can do three things to an array:Deletion, Insertion and Replacment

Deletion

Items can be deleted from the array by specifying just two arguments:

the position of the first item to delete and
the number of items to delete.

For example, splice(0, 2) deletes the first two items.

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
        var colors = ["A", "B", "C", "D", "E"]; 
        var colors2 = colors.splice(0,2); 
        document.writeln(colors); //C,D,E
       
    </script>
</head>
<body>
</body>
</html>

Click to view the demo

Insertion

Items can be inserted into a specific position by providing three or more arguments:

the starting position,
0,
any number of items to insert.

0 means deleting zero number of items from the array. You can specify a fourth parameter, or any number of other parameters to insert.

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
        var colors = ["A", "B", "C", "D", "E"]; 
        var colors2 = colors.splice(2,0,"A","B","C"); 
        document.writeln(colors); //A,B,A,B,C,C,D,E
       
    </script>
</head>
<body>
</body>
</html>

Click to view the demo

Replacement

Items can be inserted and deleted with three arguments:

the starting position,
the number of items to delete,
any number of items to insert.

The number of items to insert doesn't have to match the number of items to delete.

splice(2, 1, "A", "B") deletes one item at position 2 and then inserts the strings "A" and "B" at position 2. splice() returns an array with removed items or empty array if no items were removed.

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
        var colors = ["A", "B", "C"]; 
        var removed = colors.splice(1, 1, "D", "E"); //insert two values, remove one 
        document.writeln(colors); //A,D,E,C
        document.writeln(removed); //B
       
    </script>
</head>
<body>
</body>
</html>

Click to view the demo