function validate_field(field)
{
  if (field==null||field=="")
  {return false;}
  else{return true;}
}
function validate_fieldx(field)
{
  if (field==null||field==""||field.indexOf(']') > 0||field.indexOf('>') > 0)
  {return false;}
  else{return true;}
}
function validate_email(field)
{
apos=field.indexOf("@");
dotpos=field.lastIndexOf(".");
if (apos<1||dotpos-apos<2) 
  {return false;}
else{return true;}
}

function validate_form(thisform)
{
var naam= thisform.naam.value;
var email = thisform.email.value;
var vraag = thisform.vraag.value;
var fouten = 0;
if (validate_field(naam)==false)
{
document.getElementById('foutnaam').style.display = "";
document.getElementById('naam').className = "fout";
fouten++;
}
else{
document.getElementById('foutnaam').style.display = "none";
document.getElementById('naam').className = "formulier";
}

if (validate_email(email)==false)
{
document.getElementById('foutemail').style.display = "";
document.getElementById('email').className = "fout";
fouten++;
}
else{
document.getElementById('foutemail').style.display = "none";
document.getElementById('email').className = "formulier";
}

if (validate_fieldx(vraag)==false)
{
document.getElementById('foutvraag').style.display = "";
document.getElementById('vraag').className = "fout";
fouten++;
}
else{
document.getElementById('foutvraag').style.display = "none";
document.getElementById('vraag').className = "formulier";
}

if(fouten == 0){
return true;
}
else{
return false;
}
}