> For the complete documentation index, see [llms.txt](https://docs.helmut.de/helmut4-releases/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.helmut.de/helmut4-releases/v4.11.0/helmut4-components/streamdesigner/nodes/actions/misc/execute-javascript-action.md).

# Execute Javascript Action

Execute JavaScript Action enables the execution of JavaScript code via Nashorn, unlocking a wide range of possibilities. Its primary purpose is to facilitate integration with third-party systems for which MoovIT GmbH has not yet provided dedicated action nodes. If you require assistance, please contact us.

**Nashorn Overview and Limitations**\
Nashorn is the JavaScript engine included with Oracle’s Java 8–14 releases. It implements ECMAScript 5.1 and offers partial support for some ECMAScript 6 features, allowing Java applications to run JavaScript scripts on the JVM. However, Nashorn has several limitations to consider when using it within Execute JavaScript Action:

* **ECMAScript Support**\
  • Supports ECMAScript 5.1 fully, but only a subset of ECMAScript 6 (for example, limited support for arrow functions and template literals). Many modern JavaScript language features—such as classes, modules, and newer syntax introduced in ES2017+—are not supported.
* **Performance Considerations**\
  • Nashorn compiles scripts to bytecode at runtime, which can introduce a slight startup delay when loading large or complex scripts. For long-running integrations, this overhead is usually negligible, but you should profile performance if execution speed is critical.
* **Limited Browser API Support**\
  • Nashorn does not emulate browser-specific APIs (e.g., `window`, `document`, or DOM manipulation). Any script relying on browser globals must either be adapted to use pure JavaScript logic or augmented with custom Java-side shims.

Example javascript nashorn code which returns the result via the wildcard [stream.last\_result](/helmut4-releases/v4.11.0/helmut4-components/streamdesigner/wildcards/result-or-return-wildcards-2/stream-last_result.md) or [node result](/helmut4-releases/v4.11.0/helmut4-components/streamdesigner/wildcards/result-or-return-wildcards-2/node-result.md)

```javascript
var myInput = "test1234";
var myOutput = myInput;

myOutput;
```