Develop Reference

how do you remember a checkbox in a cookie.

i want to know how to remember a check box value in a cookie i have method createCookie.
this is the method:
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 var expires = "";
document.cookie = name+"="+value+expires+"; path=/";
}

I think that you should read this article(it is a permalink to the script, but if you have time read it all, it is very good to understand how cookie work).
However this is the code to get a cookie value:
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;
}

Javascript - Using cookies to store an integer

I am trying to use a cookie to store a single integer, so when the user refreshes the page I am able to retrieve the previous number they were on (in an attempt to stop doubles of a video appearing).
What would the minimum requirements be to accomplish this?
var randomNumber = Math.floor((Math.random()*10)+1);
document.cookie=(randomNumber);
Setting a cookie:
document.cookie = 'mycookie=' + randomNumber + ";max-age=" + (300) + ";";
Reading a cookie:
var cookie = document.cookie;
alert(decodeURIComponent(cookie));
The cookie contains some other random stuff like push=1 as well as mycookie. Should I be setting the cookie to null before I add the randomNumber?
As far as getting the value of mycookie would I just assign the cookie to a string and parse mycookie from it?

Tamil's comment is solid. Use these quirksmode functions if you ever wish to surpass minimal cookie usage:
cookie_create = function (name,value,days) {
var expires, date;
if (days) {
date = new Date();
date.setTime(date.getTime()+(days*24*60*60*1000));
expires = "; expires="+date.toGMTString();
}
else expires = "";
document.cookie = name+"="+value+expires+"; path=/";
expires = date = null;
};
cookie_read = function (name) {
var nameEQ = name + "=",
ca = document.cookie.split(';'),
len = ca.length,
i, c;
for(i = 0; i < len; ++i) {
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);
}
nameEQ = name = ca = i = c = len = null;
return null;
};
cookie_erase = function (name){
cookie_create(name,"",-1);
name = null;
};

You could use document.cookie to read/write cookies in javascript:
document.cookie = 'mycookie=' + randomNumber + '; path=/';
And if you wanted the cookie to be persistent even after the user closing his browser you could specify an expires date.

Clear all cookie using Javascript

Is there anyway to clear the cookie using javascript?
First, I need to clearify the problem. Many posts in StackOverflow give this kind of answer. But it is clearing cookie like setting the value of all the keys to empty string. But I need to erase the keys as well. How can I do that？
PS： I tried document.cookie = null, but it does not work here

The best way I found is to expire the cookie you want to delete, use this javascript:
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 var 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;
}
function eraseCookie(name) {
createCookie(name,"",-1);
}

Retrieve jQuery Cookie value

Example, I have this cookie:
$.cookie("foo", "500", { path: '/', expires: 365 });
How do I get the value of that cookie and put it into a variable?
For example (I know this is not correct):
var foo = $.cookie("foo").val();

It's just var foo = $.cookie("foo").
There's no need for a .val() call as you're not accessing the value of a DOM element.

This worked for me
function getCookieValue(cname) { // cname is nothing but the cookie value which
//contains the value
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.split(';');
for(var i = 0; i <ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}

To get the value of a cookie, you can just call it's reference. For example:
$.cookie("foo", "somevalue");
alert($.cookie("foo"));
Will alert:
somevalue

By this way we can access
console.log($.cookie()); //It will gives the all cookies in the form of object
alert($.cookie('foo'));//it will give cookie foo value ie 500

Cookie value to define style on page load

I am using the scripts from here http://www.quirksmode.org/js/cookies.html and have successfully created a cookie.. it is set based on the users response to the age drop down. However I am having trouble doing anything with it. I would like to have a style defined if a cookie is present. Here is the bulk of my scripts..
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 var 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;
}
function checkAge(){
var min_age = 13;
var year = parseInt(document.forms["emailForm"]["year"].value);
var month = parseInt(document.forms["emailForm"]["month"].value) - 1;
var day = parseInt(document.forms["emailForm"]["day"].value);
var theirDate = new Date((year + min_age), month, day);
var today = new Date;
if ( (today.getTime() - theirDate.getTime()) < 0) {
var el = document.getElementById('emailBox');
if(el){
el.className += el.className ? ' youngOne' : 'youngOne';
}
document.getElementById('emailBox').innerHTML = "<style type=\"text/css\">.formError {display:none}</style><p>Good Bye</p><p>You must be 13 years of age to sign up.</p>";
createCookie('age','not13',0)
return false;
}
else {
createCookie('age','over13',0)
return true;
};
};
window.onload=function(){
var x = readCookie('not13');
if (x) {
document.getElementById('emailBox').innerHTML = "<style type=\"text/css\">.formError {display:none}</style><p>Good Bye</p><p>You must be 13 years of age to sign up.</p>";
}
}
Age verification works and cookie is set.... no errors (from Firebug).. can anyone see what I am doing wrong?

with jQuery would be something like this
if (x) {
var style = "<style type=\"text/css\">.form {display:none}</style>";
$("header").append(style);
}

Looking at your code it should work. There's nothing incorrect about it.
The only thing I would suggest is that instead of injecting a style tag into a empty div, inject a link tag into the head. This will mean that your css changes and maintainance won't need to touch the js code.

I got it.. I was looking for the cookie value and needed to look for the name and then create an if statement based on the value. so..
var x = readCookie('age');
if (x=='not13') {
document.getElementById('emailBox').innerHTML = "<style type=\"text/css\">.formError {display:none}</style><p>Good Bye</p><p>You must be 13 years of age to sign up.</p>";
}