The PlanetScale serverless driver for JavaScript allows developers to connect to their databases over HTTP, enabling them to build serverless APIs on AWS using a Lambda function and API Gateway. To use the driver, developers need to create a database on PlanetScale, enable the beta feature, and set up environment variables. They then create a Lambda function with the driver installed, upload it to AWS, and configure API Gateway to integrate with the Lambda function. The driver supports common query types such as SELECT, INSERT, UPDATE, and DELETE, allowing developers to build RESTful APIs for their databases. With the driver, developers can also use HTTP methods to interact with their databases, enabling more flexibility in building serverless applications.