var normalS = 12;
var minS = 8;
var maxS = 20;

var nowS;

function sizeSmall(){
	if(nowS > minS){
		nowS = Number(nowS)-2;
		document.body.style.fontSize = nowS+"px";
	};
};

function sizeBig(){
	if(nowS < maxS){
		nowS = Number(nowS)+2;
		document.body.style.fontSize = nowS+"px";
	};
};

function setCookie(){
	document.cookie = "myFontSize="+nowS+"px;path=/";
}

if(navigator.cookieEnabled){
	var c = document.cookie;
	if(c.indexOf("myFontSize") != -1){
		var index = c.indexOf("myFontSize=");
		var pxIndex = c.indexOf("px",index);
		var fontS = c.substring(index+11,pxIndex);

		document.write('<style>body{font-size:'+fontS+'px;}</style>');
		nowS = fontS;
	}else{
		nowS = normalS;
	}

	if(window.addEventListener) {
		window.addEventListener("unload", setCookie, false);
	}
	else if(window.attachEvent) {
		window.attachEvent("onunload", setCookie);
	}
	else{
		window.onunload = setCookie;
	};
}else{
	nowS = normalS;
};