How do I use decimal value with ASP.NET AJAX ASP.NET AJAX NumericUpDownExtender?

I hope you know the ache of implementing ASP.NET AJAX NumericUpDownExtender with decimal values. Specially, without a web service. Anyway, practically I never face this problem before. But I picked this post from CDNUG forum.

In this example I will show to how use ASP.NET AJAX NumericUpDownExtender to increase 0.25 and decrease 0.25 with two simple web methods.