function isEmail(email) {
	//var rx = /^..+@..+\..{2,5}$/;
	var rx =/^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)*\.([a-zA-Z]{2,4})$/;
	return rx.test(email);
}


function checkform_contact(){
	if(document.contactform.firstname.value == "") {
		alert("Please insert your first name.");
		document.contactform.firstname.focus();
		return false ;
	}
	if(document.contactform.lastname.value == "") {
		alert("Please insert your last name.");
		document.contactform.lastname.focus();
		return false ;
	}

	if(isEmail(document.contactform.email.value)==false){
		alert("Please insert a valid email addresse.");
		document.contactform.email.focus();
		return false;
	}
	if(document.contactform.message.value == "") {
		alert("Please insert your message.");
		document.contactform.message.focus();
		return false ;
	}


	return true ;
}