Skip to main content

IE console.log(). It works, except when it doesn't...

So I made an interesting discovery today.

console.log() in IE9 only works when the console is open!

As a web developer, and especially a JavaScript developer, the most useful tool in your arsenal is console.log(). And while you should (for the most part) remove any console.log() calls from your code as soon as you have finished debugging, sometimes your library code might contain it, or other times if you are writing a framework for an intermediary to use, you might leave a couple of messages for your intermediaries using console.log().

console.log() first made an appearance in Firefox's Firebug (or at least that is when I first noticed it) and has been in most major browsers, including Internet Explorer since version 8. Whilst developing, I have happily had my console open so I can debug things.

Anyways, fast forward to the current app I am working on. I am lucky enough to be working on a project that uses HTML5 canvas and the project I am working on is used by a game designer (who can put in some pieces of JavaScript code) so naturally, not only do I wrap certain parts in try/catch blocks, I want to let the game designer know his code snippet has failed so I do so using console.log.

On production, we were getting some weird bugs with IE9 and I could not for the life of me figure them out because every time I opened the console, lo and behold, they disappeared. This was driving me nuts!

Until today when by chance, I opened up the site in IE9 with the console closed and I got a JavaScript debugging error telling me that console was not defined?

Huh?

I opened the console to check, and it went away. I closed the console again but I still didn't see the error. Curious...

Anyways, after some googling, I found that console.log() does not work in IE if the console has not been opened.

D'oh!

Anyways, I basically got around it by creating a mock console object if the console is not present.

i.e.

if(!(window.console && console.log)) {
  console = {
    log: function(){},
    debug: function(){},
    info: function(){},
    warn: function(){},
    error: function(){}
  };
}
(credit: http://stackoverflow.com/questions/10183440/console-is-undefined-error-in-ie9)

So there you have it...

Comments

Popular posts from this blog

Freezing Gems

What is a gem and why would you want to freeze it?

In Ruby, there are times when you want to access pieces of functionality that other people of written (3rd party libraries) and you normally have 2 options. You can install a plug in or install a gem. Normally the method you use is determined by which ever is made available by the author.

Gems are installed on the host machine and are pretty handy when you want to run things in the command line or else across lots of projects, but their downside is that if you use a gem in a Rails project there is no automatic publishing mechanism when you deploy your site. You will need to log onto the remote host machine and install the gem manually.

Plugins are specific to Rails and are similar to gems in that they are also 3rd party libraries. However they are associated with your Rails project as opposed to your machine so they will get posted to the server on a regular deploy.

Freezing a gem is the process of transforming a gem into a plug in. Essen…

Unit/Functional Testing RubyAMF

One of my current projects is using RubyAMF to communicate with Flash (http://rubyforge.org/projects/rubyamf/). On the whole this is really nice because it allows you to transfer Ruby objects directly to ActionScript ones (as opposed to translating the object into XML, sending the XML and then recreating the object in ActionScript).
However, Rails does not provide a built in transport mechanism for AMF, so we cannot run functional testing directly on the data call (as we could for an XML or HTML transport layer). This is a show stopper for a lot of people (Rails w/o Unit testing = a big mess of trouble when something goes wrong).
We can though serve both the HTML and the AMF formats depending on the request format. This means that we can test the object instantiation logic and make sure there are no errors in the controllers (though we cannot check the actual format of the data being served). In the controller, instead of rendering AMF alone, do the following respond_to do |format|

Responsive Web Design

I wanted to go over Responsive Web Design using CSS.

In the old days of web development, we had to code to common screen sizes (i.e. 800 X 600, 1024 X 768) and we patiently waited for people to upgrade their computers to have a decent amount of screen real estate so we could design things the way we really wanted. We also took on semi stretchy web layouts etc to expand and contract appropriately.

Then about 2 or 3 years ago, Apple released this little device called an iPhone with a 320 X 480 resolution which took the world by storm and suddenly a lot of people were viewing your website on a tiny screen again...

Anyways, as it can be difficult to design a site which looks good on 320 X 480 AND 1680 X 1050, we need to come up with some kind of solution.

One way is to sniff the client and then use an appropriate stylesheet, but then you are mixing CSS with either JavaScript or server side programming and also potentially maintaining a list of appropriate clients and stylesheets. Also, you ca…