Javascript Binary Search/Insertion Performance

function binarySearch(value)
{
    var startIndex = 0,
        stopIndex = words.length - 1,
        middle = Math.floor((stopIndex + startIndex) / 2);

    while (words[middle] != value && startIndex < stopIndex) {
        // adjust search area
        if (value < words[middle]) {
            stopIndex = middle - 1;
        } else if (value > words[middle]) {
            startIndex = middle + 1;
        }

        // recalculate middle
        middle = Math.floor((stopIndex + startIndex) / 2);
    }
}

I am making a large list of words in the format of an array:

e.g. ["a","ab","abc","b"]

In alphabetical order. The problem I'm having is modifying my binary search algorithm to add the word in the correct place and then update?

Whats the best way performance-wise to add a word into an ordered array? And why is it the best way to do it?

The best way is to use trees instead, since for an array such an operation is likely to have linear algorithmic complexity.

If you'd like to stick with the arrays, I suggest that you use the splice method for insertion.