send html form via post to webservice
===

I'm very very new on HTML5 development and this question could be very silly but I've found an answer for it (or I've searched very well).

I want to send a form to a web service via post (I don't want to show all fields in URL).

I have two question:

1. How must I named forms fields? If I trying to send an `userName` I think I have to put this test as ID to the field which will held that value.
2. And this is because I'm so curious. Which is the post message content which is sent to web service?

This is an example that I've found searching Internet:

     <FORM action="http://somesite.com/prog/adduser" 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"> <INPUT type="reset">
        </P>
     </FORM

I think I will need those ids to get those values while processing them on web service, isn't it?