<html>
<head>
<script>
function count_rabbits() {
document.getElementById('1').style.display="none"
document.getElementById('2').style.display=""
}
function count_rabbits2() {
document.getElementById('1').style.display=""
document.getElementById('2').style.display="none"
}
</script>
<style type="text/css">
.block1 {
width: 200px;
background: #ccc;
border: solid 1px black;
}
.block2 {
width: 200px;
background: #fc0;
padding: 5px;
border: solid 1px black;
}
</style>
</head>
<body>
<input type="button" onclick="function count_rabbits()" value="1"/>
<input type="button" onclick="function count_rabbits2()" value="2"/>
<div id="1"class="block1">1</div>
<div id="2"class="block2">2</div>
</body>
</html>