文字サイズを変更（クッキー利用）

<a href="JavaScript:;" onclick="changeTextSize(1);return false;" onkeypress="changeTextSize(1);return false;">大きく</a><br />
<a href="JavaScript:;" onclick="defaultTextSize();return false;" onkeypress="defaultTextSize();return false;">標準</a><br />
<a href="JavaScript:;" onclick="changeTextSize(-1);return false;" onkeypress="changeTextSize(-1);return false;">小さく</a><br />
<script type="text/javascript">setTextSize();</script> 

function class_cookielib(){ 
this.getCookie = getCookie; 
this.setCookie = setCookie; 
this.removeCookie = removeCookie; 

var expireDate = new Date(); 
expireDate.setFullYear(expireDate.getFullYear()+1); 
expireStr = "expires=" + expireDate.toUTCString(); 

function getCookie(name){ 
var gc=name+"="; 
var Cookie=document.cookie; 
if (Cookie.length>0) { 
var start=Cookie.indexOf(gc); 
if (start!=-1) { 
start+=gc.length; 
terminus=Cookie.indexOf(";",start); 
if (terminus==-1) terminus=Cookie.length; 
return unescape(Cookie.substring(start,terminus)); 
} 
} 
return ''; 
} 
function setCookie() { 
var key = arguments[0]; 
var val = arguments[1]; 
var path = (typeof(arguments[2]) != 'undefined' ? arguments[2] : '/'); 
var exp = (typeof(arguments[3]) != 'undefined' ? arguments[3] : expireStr); 
var sc = key + "=" + escape(val) + "; path=" + path + "; " + exp; 
document.cookie = sc; 
} 
function removeCookie(key,path) { 
if(!path){ 
path = '/'; 
} 
var rc = key + "=; path=" + path + "; expires=Thu, 1 Jan 1970 00:00:00 UTC"; 
document.cookie = rc; 
} 
} 
var cookieObj = new class_cookielib(); 

function onresize_handler(){ 
if(document.layers){ 
window.location.reload(); 
} 
} 
window.onresize = onresize_handler; 

var txtsize_val = 3; 
var txtsize_css_size = new Array(); 
txtsize_css_size[0] = '70%'; 
txtsize_css_size[1] = '80%'; 
txtsize_css_size[2] = '90%'; 
txtsize_css_size[3] = '100%'; 
txtsize_css_size[4] = '110%'; 
txtsize_css_size[5] = '120%'; 
txtsize_css_size[6] = '130%'; 
txtsize_css_size[7] = '140%'; 
txtsize_css_size[8] = '150%'; 
txtsize_css_size[9] = '160%'; 
txtsize_css_size[10] = '170%'; 
function setTextSize(){ 
if(cookieObj.getCookie('txtsize') != ''){ 
txtsize_val = 1 * cookieObj.getCookie('txtsize'); 
} 
document.write('<style type="text/css">'); 
document.write('* body { font-size:' + txtsize_css_size[txtsize_val] + '; }'); 
document.write('</style>'); 
} 

function changeTextSize(num){ 
var fl_update = false; 
var tmp_val = txtsize_val + num; 
if(tmp_val >= 0 && tmp_val < txtsize_css_size.length){ 
txtsize_val = tmp_val; 
fl_update = true; 
} 
if(fl_update){ 
cookieObj.setCookie('txtsize',txtsize_val,'/',''); 
window.location.reload(); 
} 
} 

function defaultTextSize(){ 
var fl_update = false; 
var tmp_val = 3; 
if(tmp_val >= 0 && tmp_val < txtsize_css_size.length){ 
txtsize_val = tmp_val; 
fl_update = true; 
} 
if(fl_update){ 
cookieObj.setCookie('txtsize',txtsize_val,'/',''); 
window.location.reload(); 
} 
}