function checkNewsletter()
{
  if (document.newsletter.name.value.length < 1)
  	{
	 	   alert("Please enter your name.");
		document.newsletter.name.focus();
           return false;
	}
	 
  if (document.newsletter.address.value.length < 1)
  	{
	 	   alert("Please enter your Email address.");
		document.newsletter.address.focus();
           return false;
	}

  if (document.newsletter.address.value.length > 0)
          {
          	     
          if ((document.newsletter.address.value.indexOf("@") == -1))
          {
           alert("Please enter a valid Email address, that contains an '@' and a '.'");
           return false;
          }
    
          if ((document.newsletter.address.value.indexOf(".") == -1))
          {
           alert("Please enter a valid Email address, that contains an '@' and a '.'");
           return false;
          }
		  
		  if ((document.newsletter.address.value.indexOf("ebook-library") > -1))
		  {
		   	alert("Please enter a valid Email address, and not one that contains the words 'ebook-library'");
	   		return false;
	  	  }
		
		 
      }

// default (ok)
	return true;
}