function setCookie(c_name,value,expiredays)
{
	document.cookie=c_name+ "=" +escape(value);
}

function getCookie(c_name){
	if (document.cookie.length>0){
		c_start=document.cookie.indexOf(c_name + "=");
		 if (c_start!=-1){
			c_start=c_start + c_name.length+1;
			c_end=document.cookie.indexOf(";",c_start);
			if (c_end==-1) 
				c_end=document.cookie.length;
		
			return unescape(document.cookie.substring(c_start,c_end));
			}
		}
	return "";
}			


function background(){
	var myClasses = new Array("body_gantz_revolution", "body_die", "body_caprica", "body_gantz", "body_reef", "body_fist", "body_insiders", "body_starter");
	var nTaille = myClasses.length;			
	var nElementAExecuter = 0; // valeur par defaut

	var valeurDeCookie = getCookie("premiere_visite");
					
	// si j'y suis deja passe, executer rotation
	if( valeurDeCookie ){
	//	alert( valeurDeCookie );
		nElementAExecuter = Math.floor(Math.random() * 10);
		nElementAExecuter = nElementAExecuter % nTaille;
	} else {
		setCookie("premiere_visite","1");
	}

	
	$("body").toggleClass( myClasses[ nElementAExecuter ]  );
}