<!DOCTYPE html>
<html>
<head>
<link id="cssId" rel=stylesheet href="css/css1.css">
<style>
body{font-family:Verdana; font-size:14px; line-height:24px;}
.link{cursor:pointer;}
.link:hover{text-decoration:underline;}
</style>
<script>
function css(nr)
{
a="css/css"+nr+".css";
document.getElementById("cssId").href = a;
}
</script>
</head>
<body>
<div id="css1_id" class="link">Applica <i>css1</i> (default)</div>
<div id="css2_id" class="link">Applica <i>css2</i></div>
<script>
function fnct_css1(){css(1);}
function fnct_css2(){css(2);}
document.getElementById("css1_id").addEventListener("click", fnct_css1);
document.getElementById("css2_id").addEventListener("click", fnct_css2);
</script>
</body>
</html>