Efficient way to insert a number into a sorted array of numbers?

Simple (Demo):

function sortedIndex(array, value) {
    var low = 0,
        high = array.length;

    while (low < high) {
        var mid = (low + high) >>> 1;
        if (array[mid] < value) low = mid + 1;
        else high = mid;
    }
    return low;
}

Just as a single data point, for kicks I tested this out inserting 1000 random elements into an array of 100,000 pre-sorted numbers using the two methods using Chrome on Windows 7:

First Method:
~54 milliseconds
Second Method:
~57 seconds

So, at least on this setup, the native method doesn't make up for it. This is true even for small data sets, inserting 100 elements into an array of 1000:

First Method:
1 milliseconds
Second Method:
34 milliseconds