function validateForm() {
	var name = document.getElementById("comments_name");
	var email = document.getElementById("comments_email");
	var comments = document.getElementById("comments_text");
	var err = false;
	var errmsg = "";
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(trimAll(name.value).length == 0) {
		errmsg += "\nPlease enter a valid name.";
		err = true;
	}
	if(!filter.test(email.value)) {
		errmsg += "\nPlease enter a valid email address.";
		err = true;
	}
	if(trimAll(comments.value).length == 0) {
		errmsg += "\nPlease enter your comment.";
		err = true;
	}

	if(err) {
		errmsg = "Following error(s) occurred:\n" + errmsg;
		alert(errmsg);
		return false;
	}
	else {
		document.comments_form.submit();
		return true;
	}
	return false;
}

function trimAll(sString) 
{
	while (sString.substring(0,1) == ' ') {
		sString = sString.substring(1, sString.length);
	}
	while (sString.substring(sString.length-1, sString.length) == ' ') {
		sString = sString.substring(0,sString.length-1);
	}
	return sString;
}