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Tuesday 20th April 2021

What is HTML5 Web Storage?


HTML5 Web Storage is the new cookie in town!

Although it is not strictly speaking a cookie, for privacy purposes (and compliance), we should treat it as such.

As this type of data storage is so new, (in fact it is still very much a work in progress at the time of writing), we will not get too involved in the details. Here is a brief overview of the current status:

HTML5 can store data as either localStorage or sessionStorage (the equivalent to persistent and session cookies respectively). There is a third option for databaseStorage but this has not been widely implemented yet.

The amount of data that can be stored is far greater than standard cookies, ranging from 5Mb in Firefox, Google Chrome and Opera, up to 10Mb in Internet Explorer.

The way data is stored, and the communications between your browser and the web server are much faster and more efficient than traditional cookies. This IS the way forward, so watch this space and keep an eye on W3C HTML5 Web Storage.

Can I tell if my website is using HTML5 Web Storage?

The obvious answer is to ask your web developer(s), but for the curious-minded, you could try the following...

Firstly, check to ensure that your browser is capable of Web Storage:

At the time of writing, there are only a few browsers that allow you to view/manage/delete Local Storage objects without the use of extensions or plug-ins. Please see the following:

Google ChromeGoogle Chrome 19.x
Go to Settings > Show advanced settings > Privacy/Content settings > All cookies and site data...

Click on the Local storage button. You will see the domain, size of the data, and the last modified date (but nothing else). You also have the option to remove the data.

SafariSafari 5.x
Go to Edit > Preferences > Privacy > Details...

You will see 'Local Storage' listed under the domain. You also have the option to remove the data (this will also clear the cache and any cookies that may have been set).

OperaOpera 12.x
Go to Opera Menu > Settings > Preferences > Storage

You will see the domain and size of the data. You also have the option to remove the data.

Now that you know what HTML5 Web Storage is, let's take a look at the privacy law and how it affects you.