function checkForm() {
name = document.getElementById("name").value;
email = document.getElementById("email").value;
subject = document.getElementById("subject").value;
comment = document.getElementById("comment").value;

if (name == "") {
hideAllErrors();
document.getElementById("errorname").style.display = "inline";
document.getElementById("name").select();
document.getElementById("name").focus();
return false;
} else if (email == "") {
hideAllErrors();
document.getElementById("erroremail").style.display = "inline";
document.getElementById("email").select();
document.getElementById("email").focus();
return false;
} else if (subject == "") {
hideAllErrors();
document.getElementById("errorsubject").style.display = "inline";
document.getElementById("subject").select();
document.getElementById("subject").focus();
return false;
} else if (comment == "") {
hideAllErrors();
document.getElementById("errorcomment").style.display = "inline";
document.getElementById("comment").select();
document.getElementById("comment").focus();
return false;
}
return true;
}
 
function hideAllErrors() {
document.getElementById("errorname").style.display = "none"
document.getElementById("erroremail").style.display = "none"
document.getElementById("errorsubject").style.display = "none"
document.getElementById("errorcomment").style.display = "none"
}