[javascript] Debug JavaScript in Eclipse

How can I debug JavaScript in Eclipse. I am using Eclipse 3.2.1. Everytime I click on the side it gives the option for adding bookmark but no break point.

Could anyone assist me on this?

MyEclipse (eclipse based, subscription required) and Webclipse (an eclipse plug-in, currently free), from my company, Genuitec, have newly engineered (as of 2015) JavaScript debugging built in:

You can debug both generic web applications and Node.js files.

I don't believe Eclipse has a JavaScript debugger - those breakpoints are for Java code (I'm guessing you are editing a JSP file?)

Use Firebug to debug Javascript code, it's an excellent add-on that all web developers should have in their toolbox.

In 2015, there are at least six choices for JavaScript debugging in Eclipse:

• New since Eclipse 3.7: JavaScript Development Tools debugging support. The incubation part lists CrossFire support. That means, one can use Firefox + Firebug as page viewer without any Java code changes.
• New since October 2012: VJET JavaScript IDE
• Ajax Tools Framework
• Aptana provides JavaScript debugging capabilities.
• The commercial MyEclipse IDE also has JavaScript debugging support
• From the same stable as MyEclipse, the Webclipse plug-in has the same JavaScript debugging technology.

Adding to the above, here are a couple of videos which focus on "debugging JavaScript using eclipse"

• Debugging JavaScript using Eclipse and Chrome Tools
• Debugging JavaScript using Eclipse and CrossFire (with FB)

Outdated

• The Google Chrome Developer Tools for Java allow debugging using Chrome.

For Node.js there is Nodeclipse 0.2 with some bug fixes for chromedevtools

I tried to get aptana running on my ubuntu 10.4. Unfortunately I didn't succeed. Chrome on the other hand, has an eclipse plugin that lets you debug javascript that's running in a chrome instance. Works very well. YOu'll have to install the eclipse plugin you'll find here:

http://code.google.com/p/chromedevtools/

Set Breakpoints in the javascript sources you edit in eclipse and browser your page in chrome. As soon as a javascript breakpoint is hit, the eclipse debugger halts and lets you step into, step over, browse the variables etc. Very nice!

JavaScript is executed in the browser, which is pretty far removed from Eclipse. Eclipse would have to somehow hook into the browser's JavaScript engine to debug it. Therefore there's no built-in debugging of JavaScript via Eclipse, since JS isn't really its main focus anyways.

However, there are plug-ins which you can install to do JavaScript debugging. I believe the main one is the AJAX Toolkit Framework (ATF). It embeds a Mozilla browser in Eclipse in order to do its debugging, so it won't be able to handle cross-browser complications that typically arise when writing JavaScript, but it will certainly help.

It's possible to debug JavaScript by setting breakpoints in Eclipse using the AJAX Tools Framework.

Use the debugging tools supported by the browser. As mentioned above Firebug for Firefox Chrome Developer Tools from Chrome IE Developer for IE.

That way you can detect cross-browser issues. To help reduce the cross-browser issues, use a javascript framework ie jQuery, YUI, moo tools, etc.

Below is a screenshot (javascript-debug.png) of what it looks lime in Firebug.
1) hit 'F12'
2) click the 'Script' tab and 'enable it' (if you are already on your page - hit 'F5' to re-load)
3) next to the 'All' drop down, there will be another dropdown to the right. Select your javascript file from that dropdown.
In the screenshot, I've set a break-point at line 42 by 'left-mouse-click'. This will enable you to break, inspect, watch, etc.

I'm not a 100% sure but I think Aptana let's you do that.