Add Sign-in with Facebook or Google Plus Functionality on our existing website

We are looking for developer who knows html/javascript/css and has front end development skills. Our website currently allows user to login using registered email only, developer accepted this job will add Sign-in with Facebook or Google Plus Functionality on our existing website, he/she will fix the UI both desktop and mobile responsive version. This gonna be an easy and purely front end job, we just need front end developer to add these 2 functionality, make it work, fix the UI. Once user is successfully login, developer will just need to post or redirect the data to the link given by us (e.g. login status, email and etc). We will handle everything on the back end. We will provide the login of our development server for you or your team to do the development and testing, thus no setup time is required. Requirement: - html/javascript/css/mobile responsive design - the login functionality should use the latest Facebook Javascript SDK and Google Plus Javascript SDK - should provide us what data will be return once customer is successfully login If you have working code or you have done on previous project (since these are very common functionality nowadays), that would be a great advantage. Thank you!