What is MIME type "application/x-actionscript"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-actionscript is a MIME type for ActionScript code.
It signals that the file is not plain text, but structured code meant for building interactive multimedia features.
Developers use it to code animation, games, and dynamic content in Adobe Flash projects.
Files with this MIME type typically use the AS file extension.

Helps web servers and applications identify ActionScript files.
Supports scripting in multimedia and interactive Flash environments.
Facilitates debugging and compilation of ActionScript code.

Learn more about ActionScript and its uses at Adobe.

Associated file extensions

.as

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-actionscript

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-actionscript">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-actionscript');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.as

FAQs

What is the primary use of the application/x-actionscript MIME type?

This MIME type is used to identify ActionScript source code files, which typically have the .as extension. These files contain the programming logic used to build interactive applications and games for the deprecated Adobe Flash platform.

How do I configure Apache to serve .as files?

To serve ActionScript files correctly on an Apache server, add the following line to your .htaccess file or main configuration: AddType application/x-actionscript .as. This ensures browsers and development tools recognize the file type.

Is application/x-actionscript supported in modern web browsers?

No, modern browsers do not execute raw ActionScript files, and support for the compiled Flash Player plugin has been removed from all major browsers. Today, this MIME type is primarily relevant for archival purposes or legacy development environments.

What is the difference between application/x-actionscript and application/x-shockwave-flash?

application/x-actionscript denotes the uncompiled source code (text files), whereas application/x-shockwave-flash is used for compiled SWF binaries. You write code in an .as file, but the browser (historically) played the .swf file.

How can I open a file sent with this MIME type?

Since ActionScript files are essentially plain text, you can view them using any text editor like Notepad, VS Code, or Sublime Text. To compile or run the code, you would need legacy software like Adobe Animate or Flash Builder.

How do I set up Nginx to handle application/x-actionscript?

In Nginx, you should verify that your mime.types file includes the mapping, or add it manually in your server block. Use the syntax: application/x-actionscript as; to associate the extension with the MIME type.

Can I serve .as files as text/plain instead?

Yes, serving .as files as text/plain is a safe alternative if you want the code to be readable directly in a browser window. However, using application/x-actionscript preserves the specific file identity for downloaders and IDEs.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.