Могу на js предложить
<html>
<head>
</head>
<body>
<div id="d1" style="display: block">form1 there</div>
<div id="d2" style="display: none">form2 there</div>
<button id="b1">button 1</button>
<button id="b2">button 2</button>
<script>
get=document.querySelector.bind(document)
b1=get("#b1"); b2=get("#b2"); d1=get("#d1"); d2=get("#d2")
f=function(){
switch (this){
case b1: d1.style.display="block"; d2.style.display="none"; return
case b2: d2.style.display="block"; d1.style.display="none"; return
}
}
b1.onclick=f
b2.onclick=f
</script>
</body>
</html>