gowno ali express

<style>
.left {
  float: left;
  widht: 300px;
}
.right{
  float: right;
  width: 800px;
}
.left button{
  display: block;
}
#f1, #f2, #f3, #f4 {
  display: none;
}

</style>
<div class="left">
  <button onclick="zmien('f1')">Menu1</button>
  <button onclick="zmien('f2')">Menu2</button>
  <button onclick="zmien('f3')">Menu3</button>
  <a href="#" onclick="zmien('f4')">Menu4</a>
</div>

<div class="right">

  <div id="f0">
    <h1>Ala zaczyna srać</h1>
    abcd
  </div>

  <div id="f1">
    <h1>Ala ma kota</h1>
    abcd
  </div>

  <div id="f2">
    <h1>Ala nie ma kota</h1>
    abcd
  </div>
  <div id="f3">
    <h1>Ala to kurwa</h1>
    abcd
  </div>

  <div id="f4">
    <h1>Ala sra na stojaco</h1>
    abcd
  </div>

</div>
<script>

  function zmien(id){
    if( document.getElementById(id).style.display == "block"){
        document.getElementById(id).style.display = "none";
        document.getElementById("f0").style.display = "block";
    }else {

      document.getElementById("f0").style.display = "none";
      document.getElementById("f1").style.display = "none";
      document.getElementById("f2").style.display = "none";
      document.getElementById("f3").style.display = "none";
      document.getElementById("f4").style.display = "none";

      document.getElementById(id).style.display = "block";
    }

  }
</script>