function showad(town){

    if(town == "showoverview"){
        document.getElementById("overview").style.display='block';
        document.getElementById("photos").style.display='none';
        document.getElementById("contact").style.display='none';
    }
    if(town == "showphotos"){
        document.getElementById("overview").style.display='none';
        document.getElementById("photos").style.display='block';
        document.getElementById("contact").style.display='none';
    }
    if(town == "showcontact"){
        document.getElementById("overview").style.display='none';
        document.getElementById("photos").style.display='none';
        document.getElementById("contact").style.display='block';
    }
    
}