function validate_form () {

	var why = '';

        if (document.contactform.name.value == '') {
		why += 'Please enter your name.\n';
	}
		var email_reg = /[_a-zA-Z0-9.-]+@[_a-zA-Z0-9.-]+[.][_a-zA-Z0-9.-][_a-zA-Z0-9.-]+/;
		var res = email_reg.test(document.contactform.email.value);
		if (!res) {
		why += 'Please enter a valid email address.\n';
	}
		if (document.contactform.message.value == '') {
		why += 'Please enter your message.\n';
	}
		if (why != '') {
		alert(why);
		return false;
	} else {
		return true;
	}
		
}