How do I stop constant "runtime error" messages in Internet Explorer?

We can stop them, and I’ll show you how.

But unfortunately they do indicate a problem. The good news, sort of, is
that it’s most often not your fault and there’s little you can do to “fix it”.
The best we can do is ignore it.

The error message we’re talking about looks much like this:

The “Line:” and specific error message that follows will be different.

Unless you’re a web developer, “Do you wish to Debug?” is pretty pointless.
The same thing will happen whether you say Yes or No: nothing.

There are three common causes for this error message:

• A problem on the page you are viewing. This is probably the
  most common cause. In fact the example above is exactly that – it’s a bug in the
  Javascript I’d written for a client’s web site. As a web site visitor there is
  nothing you can do to prevent or fix the error. As I said, we’ll look
  at ignoring it below.

• A problem caused by security software on your machine. Many
  security suites, in the interest of keeping you as safe as they think is
  possible, will interfere with the operation of Javascript on web sites.
  Such interference can result in errors such as the above.

• Spyware. Much spyware, and even a few viruses, will install
  themselves into your browser or otherwise interfere with it on some way. Once
  again, poorly written spyware (and much of it is surprisingly poorly written)
  can cause these errors.

Aside form making sure you’re spyware-free there’s generally little you can
do to fix the problem.

So we’ll ignore it instead.

In Internet Explorer, click on the Tools menu, then
Internet Options. In the resulting dialog click on the
Advanced tab and you should be looking at something like
this:

You’ll see two items that begin “Disable script debugging …”:

Make sure that both of those are checked, and OK your way
back out. Now you shouldn’t see that error message again.

However, be aware that you didn’t make the problem go away, you’re
just ignoring it. It’s possible that the web page you’re looking at won’t work
properly. My example above is fairly benign but there is some functionality
on that particular page that isn’t working, and won’t work until I fix my code.
Problems could range from something simple and benign to something more
serious.

But aside from ensuring that you don’t have spyware, there’s little you can
do.