I have had a search and cannot find what I need, the answers all say it is not possible and a security flaw.
However I have found a Google built website which loads content via ajax and changes the address bar and I need to find out how this is done.
Please have a look at:
http://www.thinkwithgoogle.co.uk/quarterly/people/
And see what you think
The technique you are talking about is commonly (?) known as pjax
There are several parts to get the effect you are describing:
The last part is specifically what you are asking about, but without the rest of the logic it’s not going to be too useful.