function checkValideDatum(myDate,sep)
{
 // controleer of het formaat goed is(dd-mm-yyyy)
 // de binnenkomende waarde sep is de gebruikte separator (-)
 if (myDate.length == 10) 
 {
  if (myDate.substring(2,3) == sep && myDate.substring(5,6) == sep)
  {
   var date  = myDate.substring(0,2);
   var month = myDate.substring(3,5);
   var year  = myDate.substring(6,10);
   var test = new Date(year,month-1,date);
   if (year == test.getFullYear() && (month-1 == test.getMonth()) && (date == test.getDate())) 
   {
    return true;
   }
   else 
   {
    return false;
   } 
  }
 }
}




function emailCheck (emailStr) {
/* The following pattern is used to check if the entered e-mail address
   fits the user@domain format.  It also is used to separate the username
   from the domain. */
var emailPat=/^(.+)@(.+)$/
/* The following string represents the pattern for matching all special
   characters.  We don't want to allow special characters in the address. 
   These characters include ( ) < > @ , ; : \ " . [ ]    */
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
/* The following string represents the range of characters allowed in a 
   username or domainname.  It really states which chars aren't allowed. */
var validChars="\[^\\s" + specialChars + "\]"
/* The following pattern applies if the "user" is a quoted string (in
   which case, there are no rules about which characters are allowed
   and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
   is a legal e-mail address. */
var quotedUser="(\"[^\"]*\")"
/* The following pattern applies for domains that are IP addresses,
   rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
   e-mail address. NOTE: The square brackets are required. */
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
/* The following string represents an atom (basically a series of
   non-special characters.) */
var atom=validChars + '+'
/* The following string represents one word in the typical username.
   For example, in john.doe@somewhere.com, john and doe are words.
   Basically, a word is either an atom or quoted string. */
var word="(" + atom + "|" + quotedUser + ")"
// The following pattern describes the structure of the user
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
/* The following pattern describes the structure of a normal symbolic
   domain, as opposed to ipDomainPat, shown above. */
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")


/* Finally, let's start trying to figure out if the supplied address is
   valid. */

/* Begin with the coarse pattern to simply break up user@domain into
   different pieces that are easy to analyze. */
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
  /* Too many/few @'s or something; basically, this address doesn't
     even fit the general mould of a valid e-mail address. */
	return false
}
var user=matchArray[1]
var domain=matchArray[2]

// See if "user" is valid 
if (user.match(userPat)==null) {
    // user is not valid
    // alert("The username doesn't seem to be valid.")
    return false
}

/* if the e-mail address is at an IP address (as opposed to a symbolic
   host name) make sure the IP address is valid. */
var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
    // this is an IP address
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        // alert("Destination IP address is invalid!")
		return false
	    }
    }
    return true
}

// Domain is symbolic name
var domainArray=domain.match(domainPat)
if (domainArray==null) {
	// alert("The domain name doesn't seem to be valid.")
    return false
}

/* domain name seems valid, but now make sure that it ends in a
   three-letter word (like com, edu, gov) or a two-letter word,
   representing country (uk, nl), and that there's a hostname preceding 
   the domain or country. */

/* Now we need to break up the domain to get a count of how many atoms
   it consists of. */
var atomPat=new RegExp(atom,"g")
var domArr=domain.match(atomPat)
var len=domArr.length
if (domArr[domArr.length-1].length<2 || 
    domArr[domArr.length-1].length>3) {
   // the address must end in a two letter or three letter word.
   // alert("The address must end in a three-letter domain, or two letter country.")
   return false
}

// Make sure there's a host name preceding the domain.
if (len<2) {
   var errStr="This address is missing a hostname!"
   // alert(errStr)
   return false
}

// If we've gotten this far, everything's valid!
return true;
}



function setActionContact(formulier, topic, page)
{
 // zet de hidden variabelen en submit daarna
 formulier.topicContact.value = topic;
 formulier.action = page;
 formulier.submit();
}


function setActionContactItem(formulier, topic, page, id_boek)
{
 // zet de hidden variabelen en submit daarna
 formulier.id_boek.value = id_boek;
 formulier.topicContact.value = topic;
 formulier.action = page;
 formulier.submit();
}



function setAction(huidigePagina, gekozenTaal)
{
 // zet de verborgen variabele, de actie van het form-element en submit vervolgens dit formulier
 document.menuForm.languageChosen.value = gekozenTaal;
 document.menuForm.action = huidigePagina;
 document.menuForm.submit();
}  



function setActionSearch(page,gekozenTaal,actionForm)
{
 // zet de verborgen variabele, de actie van het form-element en submit vervolgens dit formulier
 document.invoer.languageChosen.value = gekozenTaal;
 document.invoer.action = page;
 document.invoer.actionForm.value = actionForm;
 document.invoer.displayRecent.value = "no";
//alert(document.invoer.displayRecent.value);
 document.invoer.submit();

}


function setActionOrder(page,gekozenTaal,id_boek,displayall,waardenextid,waardepreviousid)
{
 // zet de verborgen variabele, de actie van het form-element en submit vervolgens dit formulier
 document.invoer.languageChosen.value = gekozenTaal;
 document.invoer.action = page;
 document.invoer.id_boek.value = id_boek;
 document.invoer.displayAll.value = displayall;
 document.invoer.waardeNextIDBASKET.value = waardenextid;
 document.invoer.waardePreviousIDBASKET.value = waardepreviousid;
 document.invoer.submit();

}





function setActionBasket(page,basketAction, gekozenTaal, id_boek, basketContent)
{
 // zet de verborgen variabele, de actie van het form-element en submit vervolgens dit formulier
 document.invoer.languageChosen.value = gekozenTaal;
 document.invoer.action = page;
 document.invoer.id_boek.value = id_boek;
 document.invoer.basketContent.value = basketContent;
 document.invoer.basketAction.value = basketAction;
 document.invoer.submit();

}





function setActionFillOrder(huidigePagina, gekozenTaal)
{
 // bepaal de inhoud van de foutmelding afhankelijk van de taal
 if(gekozenTaal=='english')
 {
  var meldingIncompleet = "Please fill in the following fields:\n* Lastname\n* Initials\n* Address\n* Postal code\n* Town or City\n* Emailaddress\n";
  var meldingEmail = "Did you correctly enter your e-mail address?";
 }
 else
 {
  var meldingIncompleet = "Wilt u de volgende velden invullen:\n* Achternaam\n* Initialen\n* Adres\n* Postcode\n* Woonplaats\n* Emailadres";
  var meldingEmail = "Heeft u uw emailadres goed ingevuld?";
 }


 var doorgaan = true;
 // controleer of alle verplichte velden zijn ingevuld
 if(document.invoer.achternaam.value==""||document.invoer.voorletters.value==""||document.invoer.postcode.value==""||document.invoer.woonplaats.value==""||document.invoer.emailadres.value=="")
 {
  alert(meldingIncompleet);
  doorgaan = false;
 }

 // controleer emailadres
 if(doorgaan)
 {
  if(!emailCheck(document.invoer.emailadres.value))
  {
   doorgaan = false;
   alert(meldingEmail);
   document.invoer.emailadres.focus();
  }
 }

 // controleer of alles goed is
 if(doorgaan)
 {
  // zet de verborgen variabele, de actie van het form-element en submit vervolgens dit formulier
  document.invoer.languageChosen.value = gekozenTaal;
  document.invoer.action = huidigePagina;
  document.invoer.submit();
 }
}