Finding duplicate values in array

by mattography

JavaScript

var arr = [9, 9, 111, 2, 3, 4, 4, 5, 7];
var sort = arr.sort();
var results = [];
for (var i = 0; i < arr.length - 1; i++) {
    if (arr[i + 1] == arr[i]) {
        results.push(arr[i]);
    }
}

alert(results);