function validates(){
	if(document.mail_form.name.value==""){
	alert("Insert your name.");
	return false;
	}
	else if(document.mail_form.email_address.value==""){
	alert("Insert your E-mail address.");
	return false;
	}
	else if(isEmail(document.mail_form.email_address.value)==false){
	alert("Invalid E-mail address.");
	return false;
	}
	else if(document.mail_form.comment.value==""){
	alert("Insert your comments.");
	return false;
	}
	else return true;
 }
	
function isEmail(_email) {
	  var emailReg = /^[a-z][a-z-_0-9\.]+@[a-z-_=>0-9\.]+\.[a-z]{2,3}$/i
	  return emailReg.test(_email);
}