[javascript] How to quickly test some javascript code?

What would be a good way to test Javascript on a browser? Should there be a localhost in my computer? and how to create one?

Install firebug: http://getfirebug.com/logging . You can use its console to test Javascript code. Google Chrome comes with Web Inspector in which you can do the same. IE and Safari also have Web Developer tools in which you can test Javascript.

Following is a free list of tools you can use to check, test and verify your JS code:

1. Google Code Playground
2. JavaScript Sandbox
3. jsbin
4. jsfiddle
5. pastebin
6. jsdo.it
7. firebug
8. html5snippet.net

Hope this helps.

If you want to edit some complex javascript I suggest you use JsFiddle. Alternatively, for smaller pieces of javascript you can just run it through your browser URL bar, here's an example:

javascript:alert("hello world");

And, as it was already suggested both Firebug and Chrome developer tools have Javascript console, in which you can type in your javascript to execute. So do Internet Explorer 8+, Opera, Safari and potentially other modern browsers.