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Are Browser Cookies Enabled?

Some site features must have cookies to work correctly.

Most shopping carts, for example, use cookies to maintain a list of what the customer has placed into the cart. Some CGI games require cookies, and some multi-page forms require cookies.

Some web sites, although they work without cookies, can provide a better visitor experience with them.

Many browsers have cookies enabled. Some don't. And some have only certain types of cookies enabled, like session cookies.

This article shows how to use JavaScript to test the visitor's browser for session cookies — the type of cookie that automatically expires when the browser is closed. The JavaScript can be placed on a different web site to test third-party cookies. Modification of the JavaScript can test persistent cookies.

A Browser Cookie Test

To test whether or not the visitor's browser is cookie-enabled, put this JavaScript somewhere into your web page. It can be in the HEAD area or the BODY.

<script type="text/javascript" language="JavaScript"> <!-- Copyright 2005 Bontrager Connection, LLC document.cookie = "TemporaryTestCookie=yes;"; if(document.cookie.indexOf("TemporaryTestCookie=") == -1) { alert("Cookies are required to use shopping cart."); } else { window.location = "http://example.com/store.html"; } //--> </script>

The above redirects the browser to http://example.com/store.html if the browser accepted the test cookie. Otherwise, an alert message is displayed.

If you do not wish to redirect or cause other actions when cookies are enabled, only to display an alert message when the cookie doesn't exist, then remove the line in the JavaScript that begins with else { window

The else { window ... code may be replaced with other actions, presenting a coupon for a special item in the store, for example.

Types of Cookies

The types of cookies relate to how long they last and who sets them.

Session Cookies

Cookie that automatically expire when the browser is closed are called session cookies. They exist only during the current browser session.

Persistent Cookies

Persistent cookies are those that will live for 1 or more days. The number of days is specified when the cookie is set.

This JavaScript will set a persistent cookie to test whether or not a browser will accept it. (Some browsers are configured to accept session cookies, but not peristent or third-party cookies.)

<script type="text/javascript" language="JavaScript"> <!-- Copyright 2005 Bontrager Connection, LLC var DaysToLive = 30; // CHANGE number 30 to number of days you want cookie to persist. var now = new Date(); then = now.getTime() + (DaysToLive * 24 * 60 * 60 * 1000); now.setTime(then); document.cookie = "TemporaryTestCookie=yes; expires=" + now.toGMTString(); if(document.cookie.indexOf("TemporaryTestCookie=") == -1) { alert("Cookies are required to use shopping cart."); } else { window.location = "http://example.com/store.html"; } //--> </script>

The above JavaScript sets the test cookie for lasting 30 days, which can be changed at the third line of the code.

Third-Party Cookies

Third-party cookies are cookies set by a domain other than the one in the browser's address bar.

Third-party cookies can be set when an element on the page (an image or the contents of an IFRAME, for examples) is provided by a different domain. That other domain sets the cookie at the time it sends the browser what it asked for.

To test whether or not a browser will accept third-party cookies, put a web page containing the JavaScript from one of the above textareas on a different domain. Then, make a web page for your regular domain that contains an IFRAME that loads the web page on that other domain. Here is an example IFRAME:

<iframe src="http://otherdomain.com/otherwebpage.html" height="50" width="50"> </iframe>

Change the SRC to the URL of the web page on the other domain.

Now, whenever the web page with the IFRAME is loaded into a browser, a third-party cookie test will be done.

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©Copyright 2005 Bontrager Connection, LLC Bontrager Connection, LLC

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