Quicksort implementation in JS.

quicksort.js

/**
 * Quicksort implementation.
 * 
 * @see {@link http://en.wikipedia.org/wiki/Quicksort}
 * @param {array} arr
 * @result {array} Sorted array
.*/
var quicksort = function(arr) {
    
    function partition(arr, left, right) {
        var pivot   = arr[Math.floor((right + left) / 2)],
            i       = left,
            j       = right,
            temp;
    
        while (i <= j) {
    
            while (arr[i] < pivot) i++;
            while (arr[j] > pivot) j--;
    
            if (i <= j) {
                temp = arr[i];
                arr[i] = arr[j];
                arr[j]= temp;
                
                i++;
                j--;
            }
        }
        
        if (i < right) 
            partition(arr, i, right);
        
        if (j > left) 
            partition(arr, left, j);
        
        return arr;
    }
    
    return partition(arr, 0, arr.length - 1);
};