function fContact(frm)
{
	if (frm['naam'].value=="")
	{
		alert("Naam is verplicht!");
		frm['naam'].focus();
		return false;
	}

	if (frm['email'].value!="")
	{
	  	apos=frm['email'].value.indexOf("@");
  		dotpos=frm['email'].value.lastIndexOf(".");
  		if (apos<1||dotpos-apos<2)
    	{
    		alert("Geen geldig e-mailadres");
    		frm['email'].focus();
    		return false;
    	}
	}
	
	if (frm['bericht'].value=="")
	{
		alert("Tekst is verplicht!");
		frm['bericht'].focus();
		return false;
	}
	
	if (frm['antispam'].value=="" || frm['antispam'].value!='15')
	{
		alert("Anti-spam vraag niet juist beanwoord!");
		frm['antispam'].focus();
		return false;
	}
	
	
	return true;
}

function isNumberKey(evt)
{
 var charCode = (evt.which) ? evt.which : event.keyCode
 if (charCode > 31 && (charCode < 48 || charCode > 57))
    return false;

 return true;
}