function check_blank_fields() {
    var themessage = "";
	if (document.loginbox.username.value == "" || document.loginbox.password.value == "") {
		themessage = "Please enter both your username and password to login.\n\n";
	}

	//alert if fields are empty and cancel form submit
	if (themessage == "") {
		document.loginbox.submit();
	} else {
		alert(themessage);
		//return false;
   	}
}