Capturing client side errors in my opinion is really good. For starters you can troubleshoot your client side implementation, but you can also make sure a js change did not break certain pages.
Below is a really simple, yet effective way to capture errors. Eventually you may want to implement something more advanced, but this will get you out of the gate.
You will need Jquery, and a server side API to accept the data. Not all browsers are currently including a Stack Trace, so you will only get stacks from certain browsers.