Set cookie and get cookie with JavaScript

I'm trying to set a cookie depending on which CSS file I choose in my HTML. I have a form with a list of options, and different CSS files as values. When I choose a file, it should be saved to a cookie for about a week. The next time you open your HTML file, it should be the previous file you've chosen.

JavaScript code:

function cssLayout() {
    document.getElementById("css").href = this.value;
}


function setCookie(){
    var date = new Date("Februari 10, 2013");
    var dateString = date.toGMTString();
    var cookieString = "Css=document.getElementById("css").href" + dateString;
    document.cookie = cookieString;
}

function getCookie(){
    alert(document.cookie);
}

HTML code:

<form>
    Select your css layout:<br>
    <select id="myList">
        <option value="style-1.css">CSS1</option>
        <option value="style-2.css">CSS2</option>  
        <option value="style-3.css">CSS3</option>
        <option value="style-4.css">CSS4</option>
    </select>
</form>

I find the following code to be much simpler than anything else:

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;
}
function eraseCookie(name) {   
	document.cookie = name +'=; Path=/; Expires=Thu, 01 Jan 1970 00:00:01 GMT;';
}

Now, calling functions

setCookie('ppkcookie','testcookie',7);

var x = getCookie('ppkcookie');
if (x) {
	[do something with x]
}

Source - http://www.quirksmode.org/js/cookies.html

They updated the page today so everything in the page should be latest as of now.

These are much much better references than w3schools (the most awful web reference ever made):

• How cookies work (quirksmode.org)
• MDN document.cookie

Examples derived from these references:

// sets the cookie cookie1
document.cookie = 'cookie1=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// sets the cookie cookie2 (cookie1 is *not* overwritten)
document.cookie = 'cookie2=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// remove cookie2
document.cookie = 'cookie2=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/'

The Mozilla reference even has a nice cookie library you can use.

I'm sure this question should have a more general answer with some reusable code that works with cookies as key-value pairs.

This snippet is taken from MDN and probably is trustable. This is UTF-safe object for work with cookies:

var docCookies = {
  getItem: function (sKey) {
    return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*" + encodeURIComponent(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=\\s*([^;]*).*$)|^.*$"), "$1")) || null;
  },
  setItem: function (sKey, sValue, vEnd, sPath, sDomain, bSecure) {
    if (!sKey || /^(?:expires|max\-age|path|domain|secure)$/i.test(sKey)) { return false; }
    var sExpires = "";
    if (vEnd) {
      switch (vEnd.constructor) {
        case Number:
          sExpires = vEnd === Infinity ? "; expires=Fri, 31 Dec 9999 23:59:59 GMT" : "; max-age=" + vEnd;
          break;
        case String:
          sExpires = "; expires=" + vEnd;
          break;
        case Date:
          sExpires = "; expires=" + vEnd.toUTCString();
          break;
      }
    }
    document.cookie = encodeURIComponent(sKey) + "=" + encodeURIComponent(sValue) + sExpires + (sDomain ? "; domain=" + sDomain : "") + (sPath ? "; path=" + sPath : "") + (bSecure ? "; secure" : "");
    return true;
  },
  removeItem: function (sKey, sPath, sDomain) {
    if (!sKey || !this.hasItem(sKey)) { return false; }
    document.cookie = encodeURIComponent(sKey) + "=; expires=Thu, 01 Jan 1970 00:00:00 GMT" + ( sDomain ? "; domain=" + sDomain : "") + ( sPath ? "; path=" + sPath : "");
    return true;
  },
  hasItem: function (sKey) {
    return (new RegExp("(?:^|;\\s*)" + encodeURIComponent(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=")).test(document.cookie);
  },
  keys: /* optional method: you can safely remove it! */ function () {
    var aKeys = document.cookie.replace(/((?:^|\s*;)[^\=]+)(?=;|$)|^\s*|\s*(?:\=[^;]*)?(?:\1|$)/g, "").split(/\s*(?:\=[^;]*)?;\s*/);
    for (var nIdx = 0; nIdx < aKeys.length; nIdx++) { aKeys[nIdx] = decodeURIComponent(aKeys[nIdx]); }
    return aKeys;
  }
};

Mozilla has some tests to prove this works in all cases.

There is an alternative snippet here:

Check JavaScript Cookies on W3Schools.com for setting and getting cookie values via JS.

Just use the setCookie and getCookie methods mentioned there.

So, the code will look something like:

<script>
function setCookie(c_name, value, exdays) {
    var exdate = new Date();
    exdate.setDate(exdate.getDate() + exdays);
    var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
    document.cookie = c_name + "=" + c_value;
}

function getCookie(c_name) {
    var i, x, y, ARRcookies = document.cookie.split(";");
    for (i = 0; i < ARRcookies.length; i++) {
        x = ARRcookies[i].substr(0, ARRcookies[i].indexOf("="));
        y = ARRcookies[i].substr(ARRcookies[i].indexOf("=") + 1);
        x = x.replace(/^\s+|\s+$/g, "");
        if (x == c_name) {
            return unescape(y);
        }
    }
}

function cssSelected() {
    var cssSelected = $('#myList')[0].value;
    if (cssSelected !== "select") {
        setCookie("selectedCSS", cssSelected, 3);
    }
}

$(document).ready(function() {
	$('#myList')[0].value = getCookie("selectedCSS");
})
</script>
<select id="myList" onchange="cssSelected();">
    <option value="select">--Select--</option>
    <option value="style-1.css">CSS1</option>
    <option value="style-2.css">CSS2</option>
    <option value="style-3.css">CSS3</option>
    <option value="style-4.css">CSS4</option>
</select>