var idNames = new Array("font_s","font_m","font_l");
function replace_css(cssName){
	var idName ;
	switch(cssName){
		case "txtsmall.css":
			idName = idNames[0];
			break;
		case "txtmedium.css":
			idName = idNames[1];
			break;
		case "txtlarge.css":
			idName = idNames[2];
			break;
	}
	
	var element = getElmByTag('link');
	var new_node = element.cloneNode(true);
	var cssUrlOld = new_node.href ;	//元のCSSURLを取得
	//新しいCSSファイル名に差し替え
	var lstIdx 	= cssUrlOld.lastIndexOf("/css/",cssUrlOld.length);
	var tCssUrl = cssUrlOld.substring(0,lstIdx) + "/css/" + cssName ;
	//CSSリンク差し替え
	new_node.href = tCssUrl;
	element.parentNode.replaceChild(new_node,element);
	
	//ボタンの数だけループ
	for(var i=0; i<idNames.length; i++){
		var elmImg = getElmById(idNames[i]);
		if(elmImg != null){
			if(idNames[i] == idName){
				setImgae(elmImg,idName + "_02.gif");
			} else {
				setImgae(elmImg,idNames[i] + ".gif");
			}
		}
	}
	
	//クッキーに保存
	setCssCookie(cssName)
}

function getElmByTag(tTagName){
	var element;
	var bytag;
	var ihref;
	var idx;
	var fname;
	
	if(document.all){
		bytag = document.all.tags(tTagName);
	} else if(document.getElementsByTagName){
		bytag = document.getElementsByTagName(tTagName);
	}
	
	// 最初のオブジェクトを取得 → 名前が一致する最初のオブジェクトを取得
	for(i=0;i<bytag.length;i++){
		ihref = bytag.item(i).href;
		idx = ihref.lastIndexOf("/",ihref.length);
		fname = ihref.substring(idx+1,ihref.length);
		if(fname == 'txtsmall.css' || fname == 'txtmedium.css' || fname == 'txtlarge.css'){
			element = bytag.item(i);
		}
	}
	return element
}

function getElmById(tID){
	var element;
	if(document.all){
		element	= document.all[tID];
	} else if(document.getElementById){
		element = document.getElementById(tID);
	}
	return element
}

function setImgae(elmImg,newName){
	var tOldUrl = elmImg.src ;
	var lstIdx 	= tOldUrl.lastIndexOf("/",tOldUrl.length);
  	var tNewUrl = tOldUrl.substring(0,lstIdx) + "/" + newName ;
  	elmImg.src  = tNewUrl;
}

var arrCookie = new Array();
function setCssCookie(tVal){
	exp=new Date();
	exp.setTime(exp.getTime()+1000*60*60*24*1);
	strCookie = "%00" + escape(tVal) ;
	
	document.cookie = "cssName=" + strCookie + "; expires=" + exp.toGMTString() + "; path=/;";
}

function getCssCookie(){
	var arrCookie = [];
	strAllCookie = document.cookie.split(";") ;
	
	var strCookie = "";
	for(var i=0;i<strAllCookie.length;i++){
		var arrParam = [] ;
		arrParam = strAllCookie[i].split("=");
		if (arrParam[0].indexOf("cssName") > -1){
			strCookie = arrParam[1];
			arrCookie = strCookie.split("%00");
			if (arrCookie[1]){
				url = unescape(arrCookie[1]);
				replace_css(url)
			}
		}
	}
}