So Im working on the next thing, sorting out a survey form using the webform module in drupal.

The problem I am encountering is that the form names are autogenerated and include hyphens.

I want to use a simple piece of code which will update a text box that shows the sum of other text boxes, but the code is having hissy fits because of said hyphens. The below works when left alone:

function startCalc(){
  interval = setInterval("calc()",1);
}
function calc(){
  one = document.autoSumForm.firstBox.value;
  two = document.autoSumForm.secondBox.value;
  document.autoSumForm.thirdBox.value = (one * 1) + (two * 1);
}
function stopCalc(){
  clearInterval(interval);
}


However if I change the fields to represent the auto-generated names:

function calc(){
  one = document.webform-client-form.submitted[food].value;
  two = document.webform-client-form.submitted[timber].value;
  three = document.webform-client-form.submitted[flood_protection].value;
  four = document.webform-client-form.submitted[soil_protection].value;
  five = document.webform-client-form.submitted[carbon_storage].value;
  six = document.webform-client-form.submitted[recreation].value;
  seven = document.webform-client-form.submitted[aesthetics].value;
  eight = document.webform-client-form.submitted[cultural_heritage].value;
  document.webform-client-form.thirdBox.value = (one * 1) + (two * 1) + (three * 1) + (four * 1) + (five * 1) + (six * 1) + (seven * 1) + (eight * 1);
}

I get all sorts of errors, mostly that client is not defined. Im guessing this is because of the -. Is it possible to escape these somehow?? Ive tried adding double and single quotes, as well as \, none works. From what I can see of the module code, changing the naming convention is out of the question...

To be brutally honest when I say java I dont know whether I mean java or javascript! I have no programming training and am simply muddling along by sheer force of will and trial and error most of the time, with lots of questions being asked on forums when I get stuck!

webform-client-form-submitted is a form field: http://www.zpyder.co.uk/tess/survey/node/2

A snippet of the form source: