Javascript Call Function and wait for its return

Question

in node.js i have a function A in which i call another function B. Function B returns an array which i need to continue in function A. However function A doesn't wait for the return value and continues. How can i manage function A to wait for the return value of function B?

functionA(param1, param 2) {
      //some code
      var content = functionB(argument);
      //some more code which needs return of functionB
}

functionB(argument) {
      //some more code
      bot.page(t).complete(function (title, text, date) {
    var str = S(text).between('== Kurzbeschreibung ==\n* ', '.').s;
            var content = {};
            str = parseTitles(str); //calls antoher function which splits a long string into an array
            content.Owner = str[0];
            content.Aim = str[1];
            content.What = str[2];
            content.Who = str[3];
            content.Steps = str[4];
            content.Page = 'anyurl';
            return content;
        }
});

}

Right now function A is not waiting until function B is finished and returns it's Value.