hmm...jeg kan ikke se helt hvorfor du ønsker å endre class verdiene, men du kan kikke litt på denne her:
<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\">
<html>
<head>
<title>Untitled</title>
<style>
P.orange{
font-family: verdana, tahoma, arial, sans serif;
font-size: 10pt;
color:#990000;
font-weight:bold;
float:left;
margin:0px;
}
</style>
<SCRIPT LANGUAGE=\"JavaScript\" TYPE=\"text/javascript\">
<!--
function changeClass( selIndex, className ){
var selVal = document.frm.selChangeClass.options[ selIndex ].value;
var valArr = selVal.split(\";\");
var styleObj = null;
if (document.all) {
for (var s = 0; s < document.styleSheets.length; s++){
for (var r = 0; r < document.styleSheets[s].rules.length; r++){
if (document.styleSheets[s].rules[r].selectorText == className){
styleObj = \"document.styleSheets[\" + s + \"].rules[\" + r + \"]\";
}
}
}
}
else if (document.getElementById) {
for (var s = 0; s < document.styleSheets.length; s++){
for (var r = 0; r < document.styleSheets[s].cssRules.length; r++){
if (document.styleSheets[s].cssRules[r].selectorText == className){
styleObj = document.styleSheets[s].cssRules[r];
}
}
}
}
if( styleObj != null ){
for( i = 0; i < valArr.length; i++ ){
arrVal = valArr[i];
styleType = arrVal.substr( 0, arrVal.indexOf(\":\") );
styleVal = arrVal.substr( arrVal.indexOf(\":\")+1);
eval( styleObj + \".style.\" + styleType + \"=\" + styleVal + \";\" );
}
}
}
//-->
</SCRIPT>
</head>
<body>
<P class=\"orange\">Dette er en liten test</P><br>
<form name=\"frm\">
<select name=\"selChangeClass\" onchange=\"changeClass( this.selectedIndex, \'P.orange\' );\">
<option value=\"fontWeight:\'bolder\'\">font-weight = bolder</option>
<option value=\"color:\'#999999\'\">farve = #999999</option>
<option value=\"color:\'#999999\';fontWeight:\'bolder\'\">alle overstående</option>
</select>
</form>
</body>
</html>
deretter kikk litt på denne link for å se hva du kan gjøre:
http://developer.netscape.com/docs/manuals/js/client/jsref/style.htm/nute