How to load the same jsp page and set user id to 0 when checkbox is selecte

Question

I hope this question isn't too amateurish to answer, but it is something that has been troubling me.
I have a jsp page page that display information about a user and has the userID passed in the link. So something like user.jsp?userID=12 for example.
On the same page I have a form with a checkbox, and a submit button, the html code is as follows:
<form name="form1" method="get" action="user.jsp">
<p><input name="userID" id="userID" type="checkbox" value="0"></p>
<p><input name="Submit" type="submit" value="Submit"></p>
</form> What I want to do is, if a user ticks the checkbox and presses Submit, I want to load the same page again, but
set the userID to zero and so the top url has the following: user.jsp?userID=0
How can I achieve this.
Thanks for all the help
Zub

Answer 1

actually I need a check code which on submit checks if the checkbox is ticked then set the value of UserID to zero. so when I press submit and before the page loads to simply does a check if its ticked? I can write the if statment but I do not know what how to check if the checkbox is ticked and were to include the code