Javascript Data Structure Tutorial - Javascript Count Occurrences

function count(arr, data) { /*from  w w w  . jav  a 2 s.c  o m*/
    var count = 0; 
    var position = binSearch(arr, data); 
    if (position > -1) { 
        ++count; 
        for (var i = position-1; i > 0; --i) { 
            if (arr[i] == data) { 
                ++count; 
            } else { 
                break; 
            } 
        } 
        for (var i = position+1; i < arr.length; ++i) { 
            if (arr[i] == data) { 
                ++count; 
            } else { 
                break; 
            } 
        } 
    } 
    return count; 
} 
function binSearch(arr, data) { 
    var upperBound = arr.length-1; 
    var lowerBound = 0; 
    while (lowerBound <= upperBound) { 
        var mid = Math.floor((upperBound + lowerBound) / 2); 
        if (arr[mid] < data) { 
            lowerBound = mid + 1; 
        } else if (arr[mid] > data) { 
            upperBound = mid -1; 
        } else { 
            return mid; 
        } 
    } 
    return -1; 
} 
var nums = []; 
for (var i = 0; i < 100; ++i) { 
    nums[i] = i; 
} 
console.log(); 
var val = 55; 
var retVal = count(nums, val); 
console.log("Found " + retVal + " occurrences of " + val + ".");