function validateForm(){
	//check email adress is in the correct format	 
	if (document.newsletterForm.emailaddress.value==""){ 
		alert("Please enter your email address!");
		document.newsletterForm.emailaddress.focus();
                    return false; 
         }
		else {var x = document.newsletterForm.emailaddress.value;
		var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
		if (!filter.test(x)){
		alert('Invalid email address');
		document.newsletterForm.emailaddress.focus();
		return false; 
		}
		}
		
		 return true;
}