JavaScript Program to Display Duplicate Values in an Array

Write a JavaScript program that find and displays number of duplicate values in an array.



Source Code
<html>
<head>
    <title>Display duplicate values in an array</title>
</head>
<body>
<script>
    var arr = [12, 14, 2, 4, 2, 41, 12, 45, 75, 41];
    var sorted_arr = arr.slice().sort();
    var duplicates = [];

    for(var i=0; i<sorted_arr.length; i++)
    {
        if(sorted_arr[i] == sorted_arr[i+1])
        {
            duplicates.push(sorted_arr[i]);
        }
    }
    document.write("Duplicate values in array are: " + duplicates);
</script>
</body>
</html>
Output