title: How to save login details for "offline" login on a php/mysql system
body: <p>I have a php/mysql login system that also has service workers incorporated for offline  functionality, i would like to be able to save login details so that the user can login when they are offline. How can I achieve this on the client?</p>
  
  <p>I have done some reading and research but haven't found anything concrete, some pointers would be great. Thanks. Something along indexedDB,local storage</p>