C# to/from JavaScript date converter

JavaScriptTimeConverter.cs

/**
 * C# <> JavaScript Date Converter
 * Copyright (c) 2011 marlun78
 * MIT License, https://gist.github.com/marlun78/bd0800cf5e8053ba9f83
 */
/// <summary>
/// Provides a Convert method to convert between C# DateTime values and JavaScript parsable Int64 date values. 
/// </summary>
public static class JavaScriptDateConverter
{
    // 
    private static DateTime _jan1st1970 = new DateTime(1970, 1, 1);

    /// <summary>
    /// Converts a DateTime into a (JavaScript parsable) Int64.
    /// </summary>
    /// <param name="from">The DateTime to convert from</param>
    /// <returns>An integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC.</returns>
    public static long Convert (DateTime from)
    {
        return System.Convert.ToInt64((from - _jan1st1970).TotalMilliseconds);
    }

    /// <summary>
    /// Converts a (JavaScript parsable) Int64 into a DateTime.
    /// </summary>
    /// <param name="from">An integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC.</param>
    /// <returns>The date as a DateTime</returns>
    public static DateTime Convert (long from)
    {
        return _jan1st1970.AddMilliseconds(from);
    }
}

Nice work!