Combining Unicode and Hex decimal

I thought this was cool whilst experimenting, I found I could use hex <strike>decimal</strike> (ooops that's what I get for posting on Monday morning) entities within a url to combine unicode strings to produce anything. The result is a truly obscure looking javascript, I've included a plain text alert to help understand what's going on, the code basically translates to javascript:x='eval' notice how it is possible to assign strings even though entities are used.

<pre lang="html"> <a href="&#x6a&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3a x=&#x27\145\166\141\154&#x27,alert(x)">Test</a> </pre>