Behind the Curtain at TCG

Debuging Dynamic JavaScript

I have always been a fan of integrated debuggers.  They really help me think about tricky bits of code and verify that my solution is correct.  While testing my code I like to use a debugger to watch all my variables and boolean conditions.  Sometimes during a walk through like this I will see some problem with a variable value that isn't manifesting to the user with any of my chosen test cases but could occur in the real world.

With JavaScript becoming a larger and larger part of my code base it's not as easy to do this.  There are some great tools that help with debugging JavaScript, and my go-to tool is FireBug.  It seems to do nearly everything for client side debugging: DOM inspection, source viewing, line by line JavaScript debugging, etc.   90% of the time it does what I need. 

There is one place that I have had trouble though:  Finding what bit of random JavaScript has been dynamically bound to the DOM.  Often the code that binds an anonymous function to some element wasn't even loaded with the page but was pulled in later due to a dynamic condition.  I am very happy to have found a tool to help with this: Visual Event.  It works by highlighting on the screen all the elements that have JavaScript bindings. When you hover over the element you can even see the code that is bound to it.

Here is what it looks like when I run it against the front page of NITRC:

If you run into some code using a lot of client side JavaScript magic, give it a try and see what you think.

SmartCEO Recognizes TCG Management Team

TCG’s president, Dan Turner, and the TCG executive management team are featured in two articles in the March issue of SmartCEO magazine. TCG’s management team is featured as one of the best senior leadership teams in Washington, DC, and is a winner of the publication’s 2012 Washington Smart CXO Awards in the Executive Management Team category, while Dan participated in the recurring “CEOForum: Interviews” column, where he was interviewed along with six other CEOs about the hiring and interview strategies that have helped make their companies successful. To read the full press release, click here.

Are you having problems with VirtualBox giving out of memory errors?

In a previous post I described how I use Virtual Machines while doing software development.   A few weeks ago I started getting memory errors when I launched a VM without closing down any other VM I had running.  Specifically, I would get a VERR_EM_NO_MEMORY error with a result code of 0x80004005.  I had never seen anything like this before and assumed that after I rebooted my computer I would see it again.  Unfortunately, it did not go away.

Running a single VM at a time isn't much of a hardship, so I didn't jump on this problem right away.  Eventually I did some research though, and it took some digging to find any relevant information. Since I had trouble finding information on the problem, I thought I would document what I found in a way that search engines could easily index: a blog post.  That way anyone else who is having a similar problem is more likely to find the solution.

Here is a link to a VirtualBox bug report on the issue.  The short story is that this problem can be resolved by killing the Google Crash Handler process.  Once I did that, I was able to start up numerous VMs as usual. 

It turns out that, for me at least, the Google Crash Manager is being launched by Chrome.  I found a related Chrome issue report.  This page explains that you can prevent the Crash Manager from running when you start Chrome in the first place.  Here are the steps:

• Hit the wrench button to the right of the address bar to pull up the Chrome menu.
• Choose Options from the menu.
• Choose "Under the Hood" from the left hand menu.
• Find the check box in the Privacy section that says "Automatically send usage statistics and crash reports to Google" and un-check that.

I expected the problem to be resolved before I had a chance to blog about it, but so far I am still seeing it.