function validateGB(){
	
    if(document.gbform.name.value==""){
        window.alert("Please fill in your name!");
		document.gbform.name.focus();
        return false;
    }
	
	 if(document.gbform.city.value==""){
        window.alert("Please fill in your city!");
		document.gbform.city.focus();
        return false;
    }

	if(!document.gbform.mail.value.match(/\b(^(\S+@).+((\.com)|(\.net)|(\.edu)|(\.mil)|(\.gov)|(\.org)|(\..{2,2}))$)\b/gi)){
        window.alert("Please fill in your valid e-mail address!");
		document.gbform.mail.focus();
        return false;
    }
	
	 if(document.gbform.msg.value==""){
        window.alert("Please write your message first!");
		document.gbform.msg.focus();
        return false;
    }
    return ;
}