simple question

Hi!
I have a simple question. Is there a way to change the values on an asp page without refreshing the page?

I am trying to send modify a variable that displays the current week on the screen and I am going to use forward and backward buttons to go forward and backward a week. Session variables are not helping me because they execute on the server and are acting very unstable. Sometimes the code works sometimes it doesn't. Can someone tell me why it behaves this way.
Any help is appreciated.

Thanks

Here is the code
Back Button
<script for = "back" event="onClick" language = "VBScript">
<% Session ("increment") = "0" %>
<% Session ("decrement") = "7" %>
window.location.reload(true)

</script>

Front Button
<input type="image" border="0" name="Forward" src="arrow5.gif" width="22" height="20" onClick="buttonClick();" >
<script for = "Forward" event="onClick" language = "VBScript">
<% Session ("increment") = "7" %>
<% Session ("decrement") = "0" %>
window.location.reload(true)
alert ("Forward")
</script>