function checkFields(form) {
missinginfo = "";
if (form.author.value == "") {
missinginfo += "\n - Name";
}
if (form.comment.value == "") {
missinginfo += "\n - Comment";
}

if (missinginfo != "") {
missinginfo ="You havn't filled these fields:\n" +
missinginfo ;
alert(missinginfo);
return false;
}
else return true;
}