reEmail = /^[\w\-_\.]*[\w\-_\.]\@(\w*\.)*[\w]+[\w]$/;
reText = /^[\w\s\-]+$/;
reBDate = /^\d\d?\/\d\d?\/\d\d\d\d$/;

function checkForm()
{
   return checkText(document.getElementById("firstname")) &&
      checkText(document.getElementById("lastname")) &&
      checkBY(document.getElementById("year")) &&
      checkText(document.getElementById("loginname")) &&
      checkText(document.getElementById("password1")) &&
      checkText(document.getElementById("password2")) &&
      checkEqual(document.getElementById("password1"),document.getElementById("password2")) &&
      checkEmail(document.getElementById("email"));

}

function checkBY(element)
{
   year = parseInt(element.value);
   if( isNaN(year) || year<1900 || year>2004)
   {
      alert("Het geboortejaar is niet correct");
      element.select();
      element.focus();
      return false;
   }

   return true;
}

function checkBD(element)
{
   if( !reBDate.test(element.value) )
   {
      alert("De geboortedatum is niet correct");
      element.select();
      element.focus();
      return false;
   }

   return true;
}


function checkText(element)
{
   if( !reText.test(element.value) )
   {
      alert("Dit veld is niet correct ingevoerd");
      element.select();
      element.focus();
      return false;
   }

   return true;
}

function checkEmail(element)
{
   if( !reEmail.test(element.value) )
   {
      alert("Het emailadres '"+element.value+"' is niet correct");
      element.select();
      element.focus();
      return false;
   }

   return true;
}

function checkEqual(elementA, elementB)
{
   if( elementA.value != elementB.value)
   {
      elementA.value="";
      elementB.value="";
      elementA.select();
      elementA.focus();
      alert("De wachtwoorden zijn niet gelijk");
      return false;
   }

   return true;
}