codice:
<HTML>
<HEAD>
<TITLE>Prova</TITLE>
</HEAD>
<BODY bgcolor=yellow>
<CENTER>
<DIV id="container1" STYLE="visibility: visible;">
   [img]sp2.JPG[/img]
</DIV>


<FORM NAME="prova">
<INPUT name="nascondi" type="button"  value="Nascondi"  onclick='document.getElementById("container1").style.display= "none";'>


<INPUT name="vedi" type="button"  value="Vedi"  onclick='document.getElementById("container1").style.display= "";'>
</FORM>

</BODY>
</HTML>