Extension3.js

(function(ext) {
    // Cleanup function when the extension is unloaded
    ext._shutdown = function() {};

    // Status reporting code
    // Use this to report missing hardware, plugin or unsupported browser
    ext._getStatus = function() {
        return {status: 2, msg: 'Ready'};
    };

    // Block and block menu descriptions
    var descriptor = {
        blocks: [
          
          [' ', 'Follow %s', 'follow', 'csf30816']
          [' ', 'Follow Kaj', 'kaj'],
          ['r', 'Your username', 'u'],
        ]
    };
    ext.follow = function (user) {
      $.ajax({
            type: "PUT",
            url: "https://scratch.mit.edu/site-api/users/followers/" + user + "/add/",
            data: {
                usernames: Scratch.INIT_DATA.LOGGED_IN_USER.model.username
            }
        })
    }
    ext.kaj = function () {
      $.ajax({
          type: "PUT",
          url: "https://scratch.mit.edu/site-api/users/followers/kaj/add/",
          data: {usernames: Scratch.INIT_DATA.LOGGED_IN_USER.model.username}
      })
    }
    ext.u = function () {
        var username = Scratch.INIT_DATA.LOGGED_IN_USER.model.username;
        return "Your username is " + username;
    }

    // Register the extension
    ScratchExtensions.register('Scratch API', descriptor, ext);
})({});