// check if the captcha code field has some text in it 
// only then enable the submit button

function check_length(form, s) {
  // return true if s is long enough
  if (s.length<4) {
    form.submit.disabled = true;
    }
  else {
    form.submit.disabled = false;
    }  
  }

function reset_form(form) {
  // make sure submit button is disabled
  form.submit.disabled = true;
  }