Try this...
------ HEAD ---------------------------------------
<link rel="stylesheet" href="style_1.css">
<link rel="stylesheet" href="style_2.css">
<link rel="stylesheet" href="style_3.css">
<link rel="stylesheet" href="style_4.css">
<link rel="stylesheet" href="style_1.css">
<script language="JavaScript">
<!--
var doAlerts=false;
function changeSheets(whichSheet){
whichSheet=whichSheet-1;
if(document.styleSheets){
var c = document.styleSheets.length;
if (doAlerts) alert('Change to Style '+(whichSheet+1));
for(var i=0;i<c;i++){
if(i!=whichSheet){
document.styleSheets[i].disabled=true;
}else{
document.styleSheets[i].disabled=false;
}
}
}
}
//-->
</script>
------- BODY ---------------------------------------
<a href="JavaScript:changeSheets(1)">Style One</a>
<a href="JavaScript:changeSheets(2)">Style Two</a>
<a href="JavaScript:changeSheets(3)">Style Three</a>
<a href="JavaScript:changeSheets(4)">Style Four</a>