javascript et class

<style type="text/css" media="all"> /*CSS3*/
.rotatetexte{
 -moz-transform: rotate(-0deg);
 -webkit-transform: rotate(-20deg);
 transform: rotate(-0deg);
}
</style>

<SCRIPT TYPE='text/javascript'>
function rottextleft(){
	var valeurairedecreation = document.getElementById('airedecreation');	
	var newairedecreation = valeurairedecreation.class?????????;
	alert("angle "+newairedecreation);
	var valeurafficheangletext = document.getElementById('afficheangletext');
	var newafficheangletext = valeurafficheangletext.value;
	newafficheangletext--;
	if (newafficheangletext > 360){
		newafficheangletext = 0;
		class.rotatetexte = newafficheangletext+"deg";	
	}
	else
	if (newafficheangletext < 0){
		newafficheangletext = 360;
	}
	valeurafficheangletext.value = newafficheangletext;
}
</script>

document.getElementById('monelement').className='rotatetexte2'