Amazon has released a developer preview of an AWS SDK for JavaScript that lets you write browser-based apps that make direct calls to AWS services.

This SDK sits alongside Amazon’s AWS SDK for Node.js for creating server-side apps in JavaScript to run on Amazon’s cloud, which we wrote about in May. The new SDK lets you make direct calls to AWS services without the need for any server-side code.

You can use the new release to make direct calls from your apps to Amazon S3 for storing and retrieving objects. You can also use Amazon SQS to read from and write to message queues, Amazon DynamoDB to store and retrieve data, and Amazon SNS for working with mobile devices and other distributed services.

The blog post about the release says the SDK supports access to all of the functionality provided by each of the services listed above, and suggest that:

“you can create and populate S3 buckets, manage message queues, create, populate, and query DynamoDB tables, and much more.”

Using the SDK looks pretty simple, essentially you only need a single script tag to start using the SDK. However, if you want to use the S3 APIs you will need to enable CORS (Cross-Origin Resource Sharing) on the target buckets. This is down from the AWS Management Console, and once enabled you can call the services that now support CORS - Amazon DynamoDB, Amazon SQS, and Amazon SNS.

The blog post has some useful advice on how to overcome the problem of needing to supply your AWS credentials without storing them in the JavaScript, though the risk of attacks on your AWS services will still worry many developers. The post also has a couple of nice examples of using the SDK. There’s both a Getting Started guide and API Documentation available on from the Amazon ASW SDK for JavaScript site, where you can also download it and the source code is available on GitHub.