defaultEmail = 'email address';

function clearField(f) {
	if (f.value == defaultEmail) {
		f.value = '';
	}
}

function unClear(f) {
	if (f.value == '') {
		f.value = defaultEmail;
	}
}

function newsletterValid(email) {
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	
	if ((email == defaultEmail) || (email == '') || !(filter.test(email))) {		
		return false;
	}
	
	return true;
 
}

function validate(){
	
	var email = $('newsletteremail').value;	
    var errorString = '';
    
    if( !newsletterValid(email) ) {
    	
    	isValid = false;
	    
    	if (email == defaultEmail) {
	        errorString = errorString + "Email Address. \n ";    
	    }	    
	    
    	else {
	        if (email.indexOf("@") == -1 || email.indexOf("@") == 0 || email.indexOf(".") == -1 || email.indexOf("@") == 0) {
	            errorString = errorString + 'Invalid email address.';    
	        }
	    }
    	
    	alert("Following fields are required:\n\n" + errorString);
        return false;
    }    
    
    //alert('adding email');
    return true;
}