In questa versione in puro JavaScript ti ci ritrovi ?
codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head><title>pure-JS toggle</title>


<script type="text/javascript">

function showHide(){

     if(document.getElementById("container").style.display=="none"){

 document.getElementById("container").style.display="";
 document.getElementById("trigger").value="Nascondi";

 } else {

 document.getElementById("container").style.display="none";
 document.getElementById("trigger").value="Mostra";

 }
}
</script>

</head><body>

<input id="trigger" value="Nascondi" onclick="showHide();" type="button">

<div id="container" style="border: 1px dashed blue"><h2>
 bla . . . <br>bla . . . bla . . . bla . . . bla . . . <br>
 bla . . . bla . . . bla . . . bla . . . </h2>
</div>

</body>
</html>