It's very easy to store key value pairs in the local browser storage from JavaScript using the new HTML5 functionality:
This demo taken from the HTML5 website and also shows a javascript function firing on a timer using the setInterval() function which executes every 5 seconds.
You can run the demo live here: http://stevenhollidge.com/html5demos/localstorage
You can run all the HTML5Rocks demos online here: http://playground.html5rocks.com
