function checkSubscribtionForm (form) {
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(form.email.value)) {
		return true;
	}else{
		alert("Email is invalid. Please enter valid email");
		return false;
	}
}