function checkmail(str){
//  var reg2 = /^[a-z0-9]+([\.%!][_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*$/; // valid
  var reg2 = /^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}$/;
  if (reg2.test(str)) { // if syntax is valid
    return true;
  }
  alert("\"" + str + "\" is een ongelding email adres !"); // this is also optional
  return false;
}
function checkdlform(form){
  if(! form.akkoord.checked){
    alert("U moet eerst akkoord gaan met de privacy statement");
    return false;
  }
  form.name.value=form.txtname.value;
  form.email.value=form.txtemail.value;
  if(form.name.value=="" || form.email.value==""){
    alert("alle velden invullen");
    return false;
  }
  if(!checkmail(form.email.value)){
    return false;
  }
  form.txtname.value="";
  form.txtemail.value="";
  return true;
}
function checkfriendform(form){
  if(form.yourname.value=="" || form.youremail.value=="" || form.friendname.value=="" || form.friendemail.value==""){
    alert("alle velden invullen");
    return false;
  }
  if(!checkmail(form.youremail.value) || !checkmail(form.friendemail.value)){
    return false;
  }
  return true;
}