document.comment_form.submit_button.onclick = function() {
	if (document.comment_form.name.value == '') {
		alert("You must provide your name.");
		document.comment_form.name.focus();
		return;
	}

	if (document.comment_form.email.value == '') {
		alert("You must provide your email address.");
		document.comment_form.email.focus();
		return;
	}

	if (document.comment_form.body_comment.value == '') {
		alert("You must provide a comment to submit this form.");
		document.comment_form.body_comment.focus();
		return;
	}
	/*
	if (document.comment_form.spam.value == '') {
		alert("You have to do the math.");
		document.comment_form.spam.focus();
		return;
	}
	if (document.comment_form.spam.value != '13') {
		alert("Check your arithmetic.");
		document.comment_form.spam.focus();
		return;
	}
	*/
	document.comment_form.action = document.comment_form.action + "&prevent=1";
	document.comment_form.submit();	
}