Lets rewind to the **days of cookies**, ok not that far as they are old but still relevant. You can set them and read them with PHP; despite the fact they are a client side technology, you can also use JavaScript, fully client side. 

Coming forward in to the future, **HTML5 Local Storage**, also a Client Side technology can not be set by PHP, you are solely reliant on JavaScript. 

It seams as though this is the reverse way of doing it (taking away not adding). Surely to have the ability to set this data with PHP is helpful and possible somehow considering Cookies can be. 

**So why isn't it possible?** What was the reasoning in not designing a way to do this?

**Update** Correct me if I am wrong, but localStorage is a [replacement of Cookies](http://blog.newrelic.com/2012/09/18/html5-web-storage-cookies-are-so-1994/), so does this not mean you are losing functionality?