What should I do when my browser tells me a script is unresponsive?

In this excerpt from
Answercast #55, I look at “not responsive” errors in browsers, typically
caused by JavaScript.

Is it my system?

Typically not. This is usually the side effect of how a web page has been
written and what it’s trying to do.

Now the script that it’s referring to is typically JavaScript. A good
example of a page that relies heavily on JavaScript in ways that can result in
this kind of behavior are things like Gmail or Facebook. Facebook’s a great
example.

JavaScript errors

So what happens is when you load up a Facebook page, it actually is running
a lot of JavaScript on your computer to lay things out. And more importantly,
to get updates as they happen without your having to refresh the page.

Now, what Firefox and Chrome are detecting here is that the JavaScript is
simply running for a long time. Longer than the programs would like it to.

What normally it expects is that the JavaScript will do something and then
finish. It will do something; it will finish; it will get an update. It will
display the update and it will be done. Then a few seconds later, it will get
the update; it will display the update; and it’s done.

If for some reason the JavaScript takes too long (where “too long” is some
random number defined by the different browsers), then the browser will complain
and say, “You know what? This script that’s running… it’s taking too long.
It’s unresponsive.”

Wait or kill

So at that point, you have two possibilities.

You can say, “Well, okay,” and wait for the script. Maybe it really is
taking too long on purpose. Maybe it really is doing something valuable.

On the other hand, you can say, “Nope, I’m impatient. Kill the script. Let’s
get on with our lives.”

Long scripts

Now, there are scenarios where it actually, very legitimately, can take too
long. I see it all the time and quite frankly, I’ll usually let a script
continue to run – because it’s usually because of a very benign (and very
common) reason that it’s just taking longer than normal. An example: again,
Facebook.

When the script is out there it’s basically going out to Facebook and
asking, “Is there something to update?” If there is, I’ll get it, I’ll display
it, and I’ll wait a few seconds; and then I’ll go back for an update,
I’ll display it, and wait a few seconds.

No response

Now, what happens if when that script starts, it asks Facebook, “Is there
an update?” and it doesn’t get a response?

Well, it waits for the response. The script is still running, but the script
is waiting for a response. If it waits too long, then your browser says, “Hey,
this script is still running. It’s unresponsive.”

The script is very legitimately waiting for something but that “something”
is simply taking longer than it normally does. It may be the case that the
response will come back from Facebook that says, “Yep, here’s some data to be
updated.” And the script will continue on; it will carry on. It will grab the
data; it will display it; and so forth. It just took longer than normal. Long
enough that the browser seemed to care.

What to do?

So, there’s really no one size fits all answer for this.

Sometimes, scripts simply take longer than the browser expects them to.
Therefore, you get this particular message to basically give you the option of
killing what might be a hung script.

It might not be; it might be something very valid, but there’s no easy way
for you and I to tell.

My advice is to let it wait.

It’ll complain again… if the script stays unresponsive, the browser will
complain again. If it complains a second time then, you know, yea, I might go
ahead and kill it. But for the most part, I’ve seen enough things (especially
with these kinds of online interactive updating kinds of scripts, that you do
find in sites like Facebook and Twitter and Gmail and so forth) that sometimes
things just take longer than you expect and it’s probably worth it letting them
continue to try for awhile.

If you get fed up… Sure, go ahead and kill ’em.