function tabnav(t){
	document.getElementById('waarom').style.display="none";
	document.getElementById('wat').style.display="none";
	document.getElementById('techniek').style.display="none";
	document.getElementById('tekst').style.display="none";
	document.getElementById('links').style.display="none";
	document.getElementById('conversie').style.display="none";
	document.getElementById('TopSEOreactions').style.display="none";

	document.getElementById('lwaarom').style.background="none";
	document.getElementById('lwat').style.background="none";
	document.getElementById('ltechniek').style.background="none";
	document.getElementById('ltekst').style.background="none";
	document.getElementById('llinks').style.background="none";
	document.getElementById('lconversie').style.background="none";
	document.getElementById('lblog').style.background="none";

	if (t == 'waarom'){
	    document.getElementById('waarom').style.display="";
	    document.getElementById('lwaarom').style.background="#fff";
	}
	if (t == 'wat'){
	    document.getElementById('wat').style.display="";
	    document.getElementById('lwat').style.background="#fff";
	}
	if (t == 'techniek'){
	    document.getElementById('techniek').style.display="";
	    document.getElementById('ltechniek').style.background="#fff";
	}
	if (t == 'tekst'){
	    document.getElementById('tekst').style.display="";
	    document.getElementById('ltekst').style.background="#fff";
	}
	if (t == 'links'){
	    document.getElementById('links').style.display="";
	    document.getElementById('llinks').style.background="#fff";
	}
	if (t == 'conversie'){
	    document.getElementById('conversie').style.display="";
	    document.getElementById('lconversie').style.background="#fff";
	}
	if (t == 'TopSEOreactions'){
	    document.getElementById('TopSEOreactions').style.display="";
	    document.getElementById('lblog').style.background="#fff";
	}
}