// valid form
function checkform(form){

  if (form.first_name.value == "") {
    alert( "Please provide your first name." );
    return false;
  }
  
  if (form.last_name.value == "") {
    alert( "Please provide your last name." );
    return false;
  }
  
  if (form.email.value == "") {
    alert( "Please provide your email address." );
    return false;
  }
  
  if (form.custom.value == "") {
    alert( "Please provide the Web address you intend to edit with Sprocket CMS." );
    return false;
  }
    
  if (form.terms.checked == false){
	alert ('You must agree to the Terms of Service in order to continue.');
	return false;
  }

  return true;
}