function regEmailUser(form)
{
     if (!validateEmailRegistrationForm(form))
          return false;
     url='modules.php?mod=email&req=email'+
          '&first='+form.first.value+
          '&last='+form.last.value+
          '&email='+form.email.value;
     var ret=serverFunction(url);
     
     // register returns the page to display upon registration.
     var object=document.getElementById('maincontent');
     object.innerHTML=ret;
     //displaydiv('headerlinks','theme/logged_in_links.html');
     mainmenu();
}


function checkEmailEmailAddress(email)
{
     // build the URL to call to check if user name is already in use.
     var url="modules.php?mod=email&req=checkemail&email="+email;
     var registerform=document.getElementById('regemailform');

     ret=serverFunction(url);

     if (ret=='false')
          {
          alert("Email address "+email+" is already in use.\nPlease choose another email address.");
          registerform.email.focus();
          return false;
          }
     return true;
}

function validateEmailRegistrationForm(form)
{

     var error_message = "The following required fields are missing:";
     var errors=0;
             
     if (isEmpty(form.first))
          {
          error_message = error_message + "\nFirst Name";
          errors=1;
          }
     if (isEmpty(form.last))
          {
          error_message = error_message + "\nLast Name";
          errors=1;
          }
     if (isEmpty(form.email))
          {
          error_message = error_message + "\nEmail";
          errors=1;
          }
     if (errors==0)
          return true;
     alert(error_message);
     return false;       
}

function isEmpty(aTextField) 
{
   if ((aTextField.value.length==0) || (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}