网页中CSS样式切换的实现

      附录：带有记忆功能的JS文档

 {
var i, a, main;
for(i=0; (a = document.getElementsByTagName
("link")[i]); i++) {
if(a.getAttribute("rel").indexOf("style") 
!= -1 && a.getAttribute("title")) {
a.disabled = true;
if(a.getAttribute("title") == title) 
a.disabled = false;
}
}
}
function getActiveStyleSheet() {
var i, a;
for(i=0; (a = document.getElementsByTagName
("link")[i]); i++) {
if(a.getAttribute("rel").indexOf("style")
!= -1 && a.getAttribute("title") && !a.disabled)
return a.getAttribute("title");
}
return null;
}
function getPreferredStyleSheet() {
var i, a;
for(i=0; (a = document.getElementsByTagName
("link")[i]); i++) {
if(a.getAttribute("rel").indexOf("style") != -1
&& a.getAttribute("rel").indexOf("alt") == -1
&& a.getAttribute("title")
) return a.getAttribute("title");
}
return null;
}
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 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;
}
window.onload = function(e) {
var cookie = readCookie("style");
var title = cookie ? cookie :
getPreferredStyleSheet();
setActiveStyleSheet(title);
}
window.onunload = function(e) {
var title = getActiveStyleSheet();
createCookie("style", title, 365);
}
var cookie = readCookie("style");
var title = cookie ? cookie :
getPreferredStyleSheet();
setActiveStyleSheet(title);