Is there a way to create and run javascript in Chrome?

Is there a way, like an extension or application, in Chrome to create and run .js files in Chrome?

if you don't want to explicitly create a js file but still want to test your javascript code, you can use snippets to run your JS code.

Follow the steps here:

1. Open Dev Tools
2. Go to Sources Tab
3. Under Sources tab go to snippets, + New snippet
4. Paste your JS code in the editor then run Command + Enter on a Mac, or Ctrl + Enter on Windows or Linux. You should see the output in console if you are using console.log or similar to test. You can edit the current web page that you have open or run scripts, load more javascript files. (Just note: this snippets are not stored on as a js file, unless you explicitly did, on your computer so if you remove chrome you will lose all your snippets);
5. You also have a option to save as your snippet if you right click on your snippet.

Try this:
1. Install Node.js from https://nodejs.org/
2. Place your JavaScript code into a .js file (e.g. someCode.js)
3. Open a cmd shell (or Terminal on Mac) and use Node's Read-Eval-Print-Loop (REPL) to execute someCode.js like this:
> node someCode.js

Hope this helps!

You should write in file:

<script>
     //write your JavaScript code here
</script>

save it with .html extension and open with browser.

For example:

// this is test.html
<script>
   alert("Hello");
   var a = 5;
   function incr(arg){
       arg++;
       return arg;
   }       
   alert(a);
</script>