function checkForm() {
name = document.getElementById("name").value;
email = document.getElementById("email").value;
comment = document.getElementById("comment").value;
if (name == "") {
hideAllErrors();
document.getElementById("nameError").style.display = "inline";
document.getElementById("name").select();
document.getElementById("name").focus();
return false;
} else if (email == "") {
hideAllErrors();
document.getElementById("emailError").style.display = "inline";
document.getElementById("email").select();
document.getElementById("email").focus();
return false;
}
return true;
} 
function hideAllErrors() {
document.getElementById("nameError").style.display = "none";
document.getElementById("emailError").style.display = "none";
document.getElementById("commentError").style.display = "none";
}