function switchinfo(target) {
  if (target == "preface") {
    document.getElementById('preface_text').style.display = "block"
    document.getElementById('butt_prefazioneon').style.display = "block"
    document.getElementById('butt_prefazione').style.display = "none"
    document.getElementById('extract_text').style.display = "none"
    document.getElementById('butt_estrattoon').style.display = "none"
    document.getElementById('butt_estratto').style.display = "block"
    document.getElementById('reviews_text').style.display = "none"
    document.getElementById('butt_recensionion').style.display = "none"
    document.getElementById('butt_recensioni').style.display = "block"
    document.getElementById('authbio_text').style.display = "none"
    document.getElementById('butt_authbioon').style.display = "none"
    document.getElementById('butt_authbio').style.display = "block"
  }
  if (target == "extract") {
    document.getElementById('preface_text').style.display = "none"
    document.getElementById('butt_prefazioneon').style.display = "none"
    document.getElementById('butt_prefazione').style.display = "block"
    document.getElementById('extract_text').style.display = "block"
    document.getElementById('butt_estrattoon').style.display = "block"
    document.getElementById('butt_estratto').style.display = "none"
    document.getElementById('reviews_text').style.display = "none"
    document.getElementById('butt_recensionion').style.display = "none"
    document.getElementById('butt_recensioni').style.display = "block"
    document.getElementById('authbio_text').style.display = "none"
    document.getElementById('butt_authbioon').style.display = "none"
    document.getElementById('butt_authbio').style.display = "block"
  }
  if (target == "reviews") {
    document.getElementById('preface_text').style.display = "none"
    document.getElementById('butt_prefazioneon').style.display = "none"
    document.getElementById('butt_prefazione').style.display = "block"
    document.getElementById('extract_text').style.display = "none"
    document.getElementById('butt_estrattoon').style.display = "none"
    document.getElementById('butt_estratto').style.display = "block"
    document.getElementById('reviews_text').style.display = "block"
    document.getElementById('butt_recensionion').style.display = "block"
    document.getElementById('butt_recensioni').style.display = "none"
    document.getElementById('authbio_text').style.display = "none"
    document.getElementById('butt_authbioon').style.display = "none"
    document.getElementById('butt_authbio').style.display = "block"
  }
  if (target == "authbio") {
    document.getElementById('preface_text').style.display = "none"
    document.getElementById('butt_prefazioneon').style.display = "none"
    document.getElementById('butt_prefazione').style.display = "block"
    document.getElementById('extract_text').style.display = "none"
    document.getElementById('butt_estrattoon').style.display = "none"
    document.getElementById('butt_estratto').style.display = "block"
    document.getElementById('reviews_text').style.display = "none"
    document.getElementById('butt_recensionion').style.display = "none"
    document.getElementById('butt_recensioni').style.display = "block"
    document.getElementById('authbio_text').style.display = "block"
    document.getElementById('butt_authbioon').style.display = "block"
    document.getElementById('butt_authbio').style.display = "none"
  }
}