KendoUI - ASP.NET MVC Defer Inline Scripts

public static class DeferHtmlHelperExtensions
{
    private const string DeferredScriptsKey = "deferredScripts";

    public static MvcHtmlString RenderDeferredScripts(this HtmlHelper htmlHelper)
    {
        var httpItems = htmlHelper.ViewContext.HttpContext.Items;

        if (!httpItems.Contains(DeferredScriptsKey)) return MvcHtmlString.Empty;

        var scripts = (IList<string>) httpItems[DeferredScriptsKey];

        var scriptBuilder = new StringBuilder(scripts.Sum(script => script.Length));

        foreach (var script in scripts.Where(script => !string.IsNullOrWhiteSpace(script)))
            scriptBuilder.AppendLine(script);

        return new MvcHtmlString(scriptBuilder.ToString());
    }

    public static MvcHtmlString Defer<TModel>(this HtmlHelper<TModel> htmlHelper, Func<HtmlHelper<TModel>, object> action)
    {
        var result = action(htmlHelper);

        string resultString = result is IHtmlString ? ((IHtmlString) result).ToHtmlString() : result.ToString();

        string html, script;

        ExtractScript(resultString, out html, out script);

        if (!String.IsNullOrWhiteSpace(script))
        {
            var httpItems = htmlHelper.ViewContext.HttpContext.Items;

            if (!httpItems.Contains(DeferredScriptsKey)) httpItems.Add(DeferredScriptsKey, new List<string>());

            var scripts = (IList<string>) httpItems[DeferredScriptsKey];

            scripts.Insert(0, script);
        }

        return new MvcHtmlString(html);
    }

    private static void ExtractScript(string input, out string html, out string script)
    {
        html = script = null;
        if (String.IsNullOrWhiteSpace(input)) return;

        var htmlBuilder = new StringBuilder();
        var scriptBuilder = new StringBuilder();

        bool isInScript = false;
        const string scriptOpen = "<script";
        const string scriptClose = "</script";

        for (int i = 0; i < input.Length; i++)
        {
            var c = input[i];

            if (c == '\r' || c == '\n') continue;

            if (isInScript)
            {
                if (IsSequentialMatch(input, i, scriptClose))
                {
                    scriptBuilder.Append("</script>");
                    var closeIndex = input.IndexOf('>', i);
                    if (closeIndex == -1) break;
                    i = closeIndex;
                    isInScript = false;
                    continue;
                }

                scriptBuilder.Append(c);
                continue;
            }

            if (IsSequentialMatch(input, i, scriptOpen))
            {
                isInScript = true;
                scriptBuilder.Append(c);
                continue;
            }

            htmlBuilder.Append(c);
        }

        html = htmlBuilder.ToString().Trim();
        script = scriptBuilder.ToString().Trim();
    }

    private static bool IsSequentialMatch(string input, int inputStartIndex, string toMatch)
    {
        if (input == null || toMatch == null || inputStartIndex < 0 || inputStartIndex >= input.Length) return false;

        for (int i = inputStartIndex; i < inputStartIndex + toMatch.Length; i++)
            if (!input[i].Equals(toMatch[i - inputStartIndex])) return false;

        return true;
    }
}