<html>
<head>
<meta charset="utf-8">
<script type="text/javascript">
function callme(){
document.getElementById("hid").style.visibility="visible";
document.getElementById("hid2").style.visibility=" hidden";
}
function hideme(){
document.getElementById("hid").style.visibility=" hidden";
document.getElementById("hid2").style.visibility=" visible";
}
</script>
</head>
<body>
<form name="myform">
<div id="hid" style="visibility: visible;">някакъв текст №1</div>
<div id="hid2" style="visibility: hidden;">някакъв текст №2</div>
<a href="javascript: callme()"> №1</a>
<a href="javascript: hideme()"> №2 </a>
</form>
</body>
</html>