[Malleys]

<form name="__my_form" method="post" action="home.php">
   <input type="hidden" name="name" value="">
   <input type="button" name="1" class="btn" value="Кнопка 1" />
   <input type="button" name="2" class="btn" value="Кнопка 2" />
   <input type="button" name="3" class="btn" value="Кнопка 3" />
</form>
<script>
  
function onClick() {
  var form = document.forms["__my_form"];
  form["name"].value = this.name;
  form.submit();  
}

for(var i = 1; i <= 3; i++)
  document.forms["__my_form"][i].onclick = onClick;
  
</script>