What Is the "Best" Way to Get and Set a Single Cookie Value Using JavaScript

What is the best way to get and set a single cookie value using JavaScript

Stolen from http://www.quirksmode.org/js/cookies.html#script

function createCookie(name,value,days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires = "; expires="+date.toUTCString();
    }
    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);
}

using it:

var oldCount = parseInt(readCookie('hitCount'), 10) || 0;
createCookie('hitCount', oldCount + 1, 7);

as pointed out in the comments, you should cast to an int since cookies are stored and returned as strings. Using foo++ or ++foo will actually cast for you, but it's safer to know exactly what you're working with:

var x = "5";  // x = "5" (string)
x += 1;       // x = "51" (string!)
x += 5;       // x = "515" (string!)
++x;          // x = 516 (number)

how to get single value by cookie in java script

I have written a small function (I could probably make this much more efficient, but I have used it for a long time) which should work for you:

function getCookieAttr(attribute) {
    var attr = attribute + "="; // create an attribute string
    var parts = document.cookie.split(';'); // split the cookie into parts
    for(var i = 0; i <parts.length; i++) { // loop through the parts for each item
        var item = parts[i];
        while (item.charAt(0)==' ') { // account for spaces in the cookie
            item = item.substring(1); // set the item
        }
        if (item.indexOf(attr) == 0) { // if the item matches the attribute
            return item.substring(attr.length,item.length); // return the value
        }
    }
    return "";
}

To use the function pass the attribute name:

document.cookie = "CookieName=grid";
console.log(getCookieAttr('CookieName'));

How do I create and read a value from cookie with javascript?

Here are functions you can use for creating and retrieving cookies.

function createCookie(name, value, days) {
    var expires;
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        expires = "; expires=" + date.toGMTString();
    }
    else {
        expires = "";
    }
    document.cookie = name + "=" + value + expires + "; path=/";
}

function getCookie(c_name) {
    if (document.cookie.length > 0) {
        c_start = document.cookie.indexOf(c_name + "=");
        if (c_start != -1) {
            c_start = c_start + c_name.length + 1;
            c_end = document.cookie.indexOf(";", c_start);
            if (c_end == -1) {
                c_end = document.cookie.length;
            }
            return unescape(document.cookie.substring(c_start, c_end));
        }
    }
    return "";
}

Any simplest way to get cookie value in javascript

You could use a javascript library, e.g. jQuery in addition with a plugin: http://plugins.jquery.com/project/cookie

Demo page: http://stilbuero.de/jquery/cookie/

How to get and set cookies in JavaScript

You can use some simple functions like setCookie() and getCookie().

You can set a cookie using the call:

setCookie('myName','value', 3);

function setCookie(name, value, days) {  var expires = "";  if (days) {    var date = new Date();    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));    expires = "; expires=" + date.toUTCString();  }  document.cookie = name + "=" + (value || "") + expires + "; path=/";}
function getCookie(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;}

I can only make a cookie have one value in javascript

You can only set one cookie at a time. To assign multiple cookies, do separate assignments:

function makeCookie() {
  document.cookie = "value=4";
  document.cookie = "pi=3.14";
  alert(document.cookie);
}

Within a cookie assignment, ; is used to add optional attributes, e.g.

document.cookie = "value=4; max-age=900";

DEMO

How to set multiple key-value pairs to one cookie?

It does not make sense to store multiple key-value pairs into one cookie, because by definition a cookie represents one key-value pair.

I believe you don't understand well how document.cookie works. It is not a standard JS string: when you set it, the cookie definition it contains is appended to the list of existing cookies. That is, you cannot set two cookies at the same time using this API.

You have two solutions:

• Use a cookie for each key-value you want to store:

  document.cookie = "myCookie=myValue";
  document.cookie = "myOtherCookie=myOtherValue";
  

• Store a single cookie with a custom serialization of your complex data, for example JSON:

  document.cookie = "myCookie=" + JSON.stringify({foo: 'bar', baz: 'poo'});
  

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