/**
 * setFontsize
 * 
 * @param fontsize
 * @param on
 * @param off
 * 
 * @need clearClassAttribute()
 * @need setClassAttribute()
 * @need setCookie()
 */

function setFontsize(fontsize, on, off) {
	var body = document.getElementsByTagName("body")[0];
	clearClassAttribute(body);
	setClassAttribute(fontsize, body);
	setCookie("fontsize", fontsize);
	
	on.setAttribute("src", on.onSrc);
	off.setAttribute("src", off.offSrc);
}

/**
 * switchFontsize
 * 
 * @need addOnload()
 * @need getCookie()
 * @need setFontsize()
 */

function switchFontsize() {
	var trigger2normal = document.getElementById("fontsize2normal");
	var trigger2large  = document.getElementById("fontsize2large");
	var cookies = getCookie();
	
	trigger2normal.offSrc = trigger2normal.getAttribute("src");
	trigger2large.offSrc  = trigger2large.getAttribute("src");
	trigger2normal.onSrc  = trigger2normal.offSrc.replace("_off", "_on");
	trigger2large.onSrc   = trigger2large.offSrc.replace("_off", "_on");
	
	trigger2normal.onclick = function() { setFontsize("normal", this, trigger2large); };
	trigger2large.onclick  = function() { setFontsize("large", this, trigger2normal); };
	
	switch(cookies["fontsize"]) {
	case "large":  trigger2large.onclick();  break;
	case "normal": trigger2normal.onclick(); break;
	default:       trigger2normal.onclick(); break;
	}
}

addOnload(switchFontsize);