How does one go about debugging javascript?

How does one go about debugging javascript?

Do you use firebug and run your page through your localhost?

If javascript is part of an ASP.NET application, I have found that the breakpoints in a .js file in Visual Studio seem to be ignored.

The problem I see is that the ASP.NET application which uses javascript code has too versions – a published and a debug version. The Debug version is located within my group of folders under the localhost. Also, when I launch the program through Visual Studio, it defaults to IE. Is there some way I can have it launch a different browser that will allow for javascript debugging?

Is there a step-by-step description somewhere?

Javascript seems to be very popular. I imagine a debugger is in use. So, what is it and how can you use it if your javascript is already part of an web site/page?


All modern browsers have a pretty powerful set of debugging tools built into them.

I normally use Chrome:

Chrome Dev Tools Tutorial
Debug JS with Firefox

With Internet Explorer or Chrome just press F12. For Opera hold down Ctrl and Shift and press I. Only Firefox doesn’t have a debugger built in.

Firefox 23 seems to have… Ctrl + Shift + S

I guess that they are not too many years behind Internet Explorer now then IE has only had one built in since version 8.