function tabnav(t){
	document.getElementById('why').style.display="none";
	document.getElementById('what').style.display="none";
	document.getElementById('technique').style.display="none";
	document.getElementById('content').style.display="none";
	document.getElementById('links').style.display="none";
	document.getElementById('conversion').style.display="none";
	document.getElementById('TopSEOreactions').style.display="none";
	
	document.getElementById('lwhy').style.background="none";
	document.getElementById('lwhat').style.background="none";
	document.getElementById('ltechnique').style.background="none";
	document.getElementById('lcontent').style.background="none";
	document.getElementById('llinks').style.background="none";
	document.getElementById('lconversion').style.background="none";
	document.getElementById('lblog').style.background="none";
	
	if (t == 'why'){
	    document.getElementById('why').style.display="";
	    document.getElementById('lwhy').style.background="#fff";
	}
	if (t == 'what'){
	    document.getElementById('what').style.display="";
	    document.getElementById('lwhat').style.background="#fff";
	}
	if (t == 'technique'){
	    document.getElementById('technique').style.display="";
	    document.getElementById('ltechnique').style.background="#fff";
	}
	if (t == 'content'){
	    document.getElementById('content').style.display="";
	    document.getElementById('lcontent').style.background="#fff";
	}
	if (t == 'links'){
	    document.getElementById('links').style.display="";
	    document.getElementById('llinks').style.background="#fff";
	}
	if (t == 'conversion'){
	    document.getElementById('conversion').style.display="";
	    document.getElementById('lconversion').style.background="#fff";
	}
	if (t == 'TopSEOreactions'){
	    document.getElementById('TopSEOreactions').style.display="";
	    document.getElementById('lblog').style.background="#fff";
	}
}