I’m developing a proof of concept web application based on angular.js for corporate users, which – as so often in my career – means that they are using Internet Explorer. Several users complained about sporadic failures which were really hard to pin down, but during debugging sessions boiled down to a simple observation: the errors might or might not happen, but they never occurred when IE’s developer console was open.
The culprit turned out to be, believe it or not, console.log. I knew that some older IE versions didn’t have the console object, but having used it for development quite a while now I thought that IE 9 supports it. I learned recently that this is only conditionally true [1]. The console object will exist only if an actual developer console is open and visible.
A safe workaround seems to be declaring it if it’s missing:
if (typeof console == "undefined") {
window.console = {
log: function () {}
};
}
Surprisingly this code even covers the corner case of the developer console not being initially visible but being later opened by the user: when the user opens a developer console, it will override the mock console and everything is peachy.
Resources
[1] Does IE9 support console.log, and is it a real function?
http://stackoverflow.com/questions/5472938/does-ie9-support-console-log-and-is-it-a-real-function
George's Techblog 