JavaScript Debugging Tools

Cross-browser

qooxdoo Inspector

Firebug Lite

JS Shell

Fiddler

While there is some nice integration with Internet Explorer, Fiddler works together fine as an analyzing proxy with any web browser.

Homepage

Wireshark / Ethereal

Wireshark is the successor of the tool formerly known as "Ethereal" (which is not being actively continued).

Homepage

Firefox

JavaScript Console

Firebug

Venkman

DOM Inspector

Web Developer Extension

Tamper Data

Fasterfox

Internet Explorer

JavaScript Console

Microsoft Windows Script Debugger

Microsoft Script Editor

May be installed as part of MS Office and/or MS Frontpage.

There is a bug that causes the debugger to get unattched from the current document. If this happens, open a new browser window (via menu File/New Window) and close the original window.

Visual Web Developer

Developer Toolbar

JScript Profiler

JavaScript Memory Leak Detector

Info

Opera

JavaScript Console

Developer Console

Opera 9.0 and later.

Homepage

DOM Snapshot

Opera 9.0 and later.

Homepage

Safari / WebKit

"Debug" menu

Turn the "Debug" menu on under Mac OS X or Windows .

JavaScript Console

Drosera