So A < a, which means if you use the sort() function and your array contains elements starting with upper and lowercase then the uppercase will appear first, i.e.:

Art, ASP.NET, LawDeed, LINQ will appear as:
ASP.NET
Art
LawDeed
LINQ

To get this working correctly you need the following function:

    charOrdA: function(a, b) {
        a = a.toLowerCase(); b = b.toLowerCase();
        if (a > b) return 1;
        if (a < b) return -1;
        return 0;
    }

This function will make sure your alphabetical sortorder is correct so that the list appears like this:
Art
ASP.NET
LawDeed
LINQ

You have to pass the function name to the sort function like this:

arrCategories.sort(charOrdA);

Note that there are no parenthesis.