how to improve the speed of postback? if do not talk about internet speed

i have 100 buttons and 101 textboxs, button run scripts and some of them run by code like this:
Protected Sub bt00_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles bt00.Click
    Dim txt00 As Integer
    Dim txt1 As Integer
    txt1 = CInt(IIf(TextBox1.Text.Trim = "", 0, TextBox1.Text.Trim))
    txt00 = CInt(IIf(textbox00.Text.Trim = "", 0, textbox00.Text.Trim))
    Dim max1 As Integer = 1000
      If txt1 + txt00 > max1 Then
        textbox00.Text = txt00
        Label1.Text = "max is 1000"
     Else
         textbox00.Text = txt1 + txt00
      End If
    End Sub
i meaen i want it run on client side only , before i submit ...