function tabSwitch_2(active, number, tab_prefix, content_prefix) {  
      
    for (var i=1; i < number+1; i++) {  
      document.getElementById(content_prefix+i).style.display = 'none';  
      document.getElementById(tab_prefix+i).className = '';  
    }  
    document.getElementById(content_prefix+active).style.display = 'block';  
    document.getElementById(tab_prefix+active).className = 'active';      
      
}  
function OpenIDCheck(form)
{
	if(form.openid_url.value.length==0)
	{
		window.alert("Het URL veld is leeg! Type uw OpenID profiel in");
		form.openid_url.focus();
		return false;
	}
	return true;
}
function Check2(form)
{
	if(form.yourname.value.length==0)
	{
		window.alert("Voer uw naam in!");
		form.yourname.focus();
		return false;
	}
   if(form.yourmail.value.length==0)
	{
		window.alert("Voer een geldig e-mailadres in!");
		form.yourmail.focus();
		return false;
	}
    var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	
	if (!filter.test(form.yourmail.value)) {
	window.alert("Voer een geldig e-mailadres in!");
	form.yourmail.focus();
	return false;
	}
	
    if(form.comment.value.length==0)
	{
		window.alert("Voer uw reactie in!");
		form.comment.focus();
		return false;
	}
return true;
}