Capturing JavaScript error in Selenium

Question

Is there a way to capture errors occurring in the DOM in Selenium and probably flag the same as an error in the page?

To give a brief exam

Answer 1

Solution with "window.onerror" didn't work for me.

So I'd like to point out another solution with altering user-extensions.js which helped me:
Can Selenium detect if the page has JavaScript errors?

Main advantage: You don't have to change the page source to do the check.

And here is how to use user-extensions.js:
Using User-Extensions With Selenium-IDE

Note: This solution works only with Firefox