# Tutorial: Write Your First JavaScript Program
JavaScript programs execute in the browser. That means you need an HTML document. Here is a simple one to start with:
```html
My document
```
That is a very basic HTML document that doesn’t do much. For now, save it to a file named `helloworld.html`. The `.html` extension indicates that the file is an HTML document.
Now add JavaScript to the HTML document. Write JavaScript code inside a `` element:
```html
My document
```
This JavaScript code declares a variable `s` and assigns the string `"Hello, world."` to it.
Next, it outputs `s` to the document.
Finally, it outputs `s` to the console.
To execute the JavaScript code, double-click the `helloworld.html` file. The program will execute in your browser. Note the output in the body of the document.
To see the console output, view the browser console:
* Right-click anywhere in the document and click *Inspect*.
* Expand the browser window wide.
* Click the *Console* tab in the top-right.
🏆 Congratulations! That’s your first JavaScript program!
Now you can explore and learn the rest of the JavaScript language.
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