How to pass Query-string from ASPX file

Hi
I have a textbox in my page and a button. I want whenever I click on the button the text written in the textbox passed on a newpage as a querystring. 
Forexample, in the following example I want to pass text written in the text box as ID in teh query string instead of X which I passed in my example.
<a href="WebForm2.aspx?ID=X">Page2</a>

Thank you:)
EDIT: I have an <a href> not a button. I corrected my post after the first answer! Thanks :)
...