function checkAantal(aantal) {

			val = parseInt(aantal);

			if (isNaN(val))

				return 0;

			if (val <= 0)

				return 0;

			return val;

		}

		function validate() {

			with (document.myform) {

				if (refDag.selectedIndex == 0)

				{

					alert("Bitte wähle einen Tag aus.");

					return false;

				}

				if (refMaand.selectedIndex == 0)

				{

					alert("Bitte wähle einen Monat aus.");

					return false;

				}

				if (refJaar.selectedIndex == 0)

				{

					alert("Bitte wähle ein Jahr aus.");

					return false;

				}

				if (duration.selectedIndex == 0)

				{

					alert("Bitte gib die Anzahl der Tage deiner Periode an.");

					return false;

				}

				days = checkAantal(cyclus.value);

				if ((days <= 10) || (days >= 80))

				{

					alert("Bitte gib eine Zahl für die Länge deines Zyklus an.");

					return false;

				}

			}

			return true;

		}

		function mySubmit() {

			if (validate()) document.myform.submit();

		}	

function navigate(link) {
	
		var links=['yourbody','yourmind','beauty','sexrel','askanna','advice','vip'];
		for(i=0;i<links.length;i++) {			
	       var obj=document.getElementById(links[i]);
    	   var visible=(obj.style.display != "none");	
    	   // Here we will switch between expand and collapse
	       if(visible){
    	      obj.style.display = "none";
	       }else{
		   		if(links[i]==link) {
	    	      obj.style.display = "block";
				}
	       }		
		}
       // Let's get the object and check the status using visible variable
    }	
	
function MM_preloadImages1() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages1.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj1(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj1(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_showHideLayers1() { //v6.0
  var i,p,v,obj,args=MM_showHideLayers1.arguments;
  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj1(args[i]))!=null) { v=args[i+2];
    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }
    obj.visibility=v; }
}

function MM_goToURL1() { //v3.0
  var i, args=MM_goToURL1.arguments; document.MM_returnValue = false;
  for (i=0; i<(args.length-1); i+=2) eval(args[i]+".location='"+args[i+1]+"'");
}

function MM_swapImgRestore1() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_swapImage1() { //v3.0
  var i,j=0,x,a=MM_swapImage1.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj1(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}