function checkform ( form )
{
  if (form_subscribe.text_first_name.value == "") {
    alert( "Please enter your first name" );
    form_subscribe.text_first_name.focus();
    return false ;
  } 
  if (form_subscribe.text_email_address.value == "") {
    alert( "Please enter an email address" );
    form_subscribe.text_email_address.focus();
    return false ;
  }
  if (!isValidEmail(form_subscribe.text_email_address.value)) {
	alert("Please enter a valid email address"); 	
    form_subscribe.text_email_address.focus();
    return false;
  }
  return true ;
}

function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0)
}