What is a good Javascript debugging tool?

Question

Haven\'t touch javascript for 3 years. Just got a javascript project and wanted to know any new ways or tools emerged these years to debug javascript? I used alert 3 years

Answer 1

I use Javascript Debugger plugin to debug errors that are not easy to figure out in firebug. You can set up break points and step through problem area to see variable values..etc. It's a very useful tool.