implementing button - HTML

Question

i am using python, and appengine, and i am trying to fix a specific button.

let's say this is the code :

<FORM action="http://blabla" method="post">
    <P>
    <LABEL for="firstname">First name: </LABEL>
              <INPUT type="text" id="firstname"><BR>
    <LABEL for="lastname">Last name: </LABEL>
              <INPUT type="text" id="lastname"><BR>
    <LABEL for="email">email: </LABEL>
              <INPUT type="text" id="email"><BR>
    <INPUT type="radio" name="sex" value="Male"> Male<BR>
    <INPUT type="radio" name="sex" value="Female"> Female<BR>
    <INPUT type="submit" value="Send"> 
</form>

now, all i need is the "sumbit" button (send) and i need it to have a name. i mean, i want a button that with only a click will change a global variable in my code.

for example i will try to do :

name = self.request.get("name")

I wanted to know what is the most elegant way to implement it.

Thanks.