function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name) {
	createCookie(name,"",-1);
}

function showNavi() {

var param = readCookie('navi');

var ImgURL = document.getElementById("navibutton").src;


    if (param == "off") {
            document.getElementById("headnavi").style.display = "";
	    document.getElementById("navibutton").src = ImgURL.replace(/einblenden/g, "ausblenden");
	    document.getElementById("navitext").innerHTML = "Navigation ausblenden";
	    createCookie('navi','on',7)
	} 
	else if (param == "on") {
	    document.getElementById("headnavi").style.display = "none";
	    document.getElementById("navibutton").src = ImgURL.replace(/ausblenden/g, "einblenden");
	    document.getElementById("navitext").innerHTML = "Navigation einblenden";
	    createCookie('navi','off',7)
	}
}